Can I change my caste, because my parents are intercaste

There would not be any issue to change your cast matching the same as that of your mother. But the question is you are thirty year old and by this time, you might have different qualifications and in all such qualifications, title of the cast is to be changed accordingly - from SC to Brahmin. To make such changes effective, you will have to approach the different Boards/ Universities to change the title as per order of District Education Officer consuming inordinate time.
The best recourse would be to approach a lawyer taking the case of Notary Magistrate and he will make a draft on your behalf to change your present title to your mother's title. Below the content of this version, you will have to put your initial and the same would countersigned by the Rotary Magistrate. This will be the valid affidavit and afterwards a notification is to be displayed in two papers one in English Daily and other one in the local newspaper. Preserve this cutting to be produced before the document verification authorities.
Go to Aadhar Centre for changing your title on the basis of this affidavit.
Similarly all your official records including Passbook of the Bank has to changed as per your present format.

Earlier days the caste of the baby born to a couple belonging to different castes is the same as that of the father. But there is a change in that aspect. The children shall be considered to be belonging to either the caste of the father or the mother according to the declaration of parents regarding the way of life in which the children are brought up. In some cases, the court has also agreed for the proposal of the candidate and agreed that the child can take the caste of the mother also.
Now you are 30 years old and you might have completed your education and maybe in a job. So now why you want to change. During your education did you used reservation facility that is being given to SC candidates. Then did you use SC caste reservation facility for a job? These things are also to be seen. If you availed those reservations and now you want to change the caste means there may be some legal issue. So you have to think in those lines. You should not be in problems by changing the caste.
I advise you to go to a lawyer and explain to him the entire case and take his opinion and proceed in that direction.
In case you have not utilised the reservation policy for your education and employment you can change the caste but you have to explain the reason why you are opting a change. This aspect also you can discuss with a lawyer. He will advise you whether you can change the caste by getting an affidavit done or you have to file a case in the court and proceed accordingly.

I do not know how a change of caste through some legal ways is a progressive decision and why you are choosing it when you are 30 years old now. It's not an easy task because already there is a Supreme Court judgement that says a person's caste is decided by birth and a child born in the family of a particular caste cannot change her/his caste in any way and the caste remains the same even after marriage.

But there is also a ruling that says children of inter-caste marriages can decide their castes based on various circumstances. In general, for inter-caste marriages, it is presumed that the child belongs to the caste of the father. But depending upon the upbringing, the child can take the caste of the mother. For instance, if the father is of upper caste and the mother is of SC/ST the child can take the caste of the mother if the circumstance compels the mother to raise the child. In that case, the child is entitled to all the benefits of SC/ST. In your case, I am sure you have completed your education and may have mentioned your caste in most of the application forms while applying for various courses. Since you said that somebody told you can choose your mother's caste now, I am sure till now you belong to your father's caste and people in your locality know that you belong to SC. If you have already availed the benefits of SC as a student then legally you are not allowed to change your caste.

You may approach the local authorities like the DM/SDM or Collector's office that issue caste certificates and have a talk with them to know whether there is a way to do it. It's not something like since you wish to change your caste you can change it. I do not know about your upbringings or present condition, but if your caste is already mentioned somewhere as SC then it will not be possible to change it unless there is valid legal purpose.

A person born out of an inter-caste marriage, after attaining an age of 21 years, can go for change of his caste from his father's caste to mother's cast. This facility is only for the inter-caste marriages. So, there is a provision for that but for doing anything there should be a motive. Just doing something for the false prestige in society or show off is not a motive. If you have a genuine motive for doing that then you can very well consult a lawyer and start the process of applying for it or getting it declared based on a magistrate verified affidavit prepared on the prescribed non-judicial stamp papers. It might require gazette notification also associated with the name change subsequent to caste change.

For other people who are born to same caste parents, change in caste is not allowed by the law. It is interesting to note that they can change their religion if they so wish but not the caste.

One thing which would be of crucial importance here is that in your case you want to change it from SC to Brahmin. But you might had taken some advantages of being SC till now. Those advantages would not accrue to you in future. If some advantage is continuing as on date it would be immediately discontinued. There would not be any advantage in future to your children also.

One more thing which is also very important is that once you change your caste would you change your name also or keep it just like that. If you have to change it then it would be a big pandora box opening for you as you will have to go for so many name change formalities and gazette notifications for all your mark sheets, certificates etc. The PAN card and Aadhar card would also require necessary changes in the name. You can see the pros and cons of this caste change thing vis-à-vis your perceived gain or satisfaction in doing that and then only take a conscious decision.

Children born to an intercaste couple have choice to adopt the caste of father or mother as per their liking but that can be exercised only when they turn adult that is after the age of 21 years. Before that whatever caste their parents have written at the time of admission to the school becomes their caste and whatever benefits are allowed for that caste would be accrued to them naturally. You have not spelled out the exact reason behind your changing of your caste at this juncture as it appears a lot of inconvenient from the angle of changing your records at various places in the identity card, voter card, employee card, bank account and debit cards, Aadhar card, PAN card, educational testimonials, Passport, Ration card and many more where a change of name might be required subsequent to the caste change. So, I was just thinking whether it is worth to take so much of trouble in getting so many changes there just because you want to make a change in your caste followed by a change in your name if the caste is coming in it as a surname or middle name or whatever other way.

In case you have some personal or compelling reasons to do so then it is imperative that you would have to take the help of a lawyer in the matter because not only a legal affidavit would be required but also for name change the usual procedure of giving intimation in local newspaper and gazette notification would also be required. That is the procedure that has to be adopted for making your documents in order.

In our Indian culture after the marriage the girls drop their surname and adopt the husbands surname. This was alright earlier but now as women are also serving and have so many credentials many women are keeping their original surname to avoid the hassles of changing their name in so many places and also in educational credentials. You can take some inspiration in your case from there also if you feel it ok.

Normally children get the legacy of following the father caste and you are being 30 years old now you have the right change to any caste on your own without compulsion. If you want to embrace the Brahmin caste, you are most welcome and there must be a society or brahmin trust in your area, please approach them they will do the needful. Because after you changed the caste. they would give you the certificate which becomes the basic document for you to apply to the MRO office to seek for government caste certificate cancelling the old and incorporating the new caste against your name. Once you get the Caste certificate from the MRO that becomes the legal binding for all and what ever you have been enjoying against the old caste will be ceased and stopped. And to that affect a public advertisement on news papers would be asked to be released by the concerned authorities.