Cricket is a game for everyone. Age is just a number. It's not a matter of concern if you are fit and willing to be fit in future. Instead of extending it too long, here I am going to give you some useful points to start with:
1st- Believe that you can: Yes, if you don't believe, then it's useless. Remember that you have to directly force your way in the Ranji team which is 10000 times tougher than we think. You will have to wait and be patient. As Mahesh sir pointed out that Pravin Tambe made IPL debut at 43, this is not only story of a sportsman who made his professional debut late. Jim Morris made a Major league debut at 35. Vijag Awate played Ranji trophy at 31. There are many players who made International debut when they were over 30 and still went on to become decent players. Michael Hussey is one of them. So if they can, why you can't?
2nd- Join a cricket academy: Find out a cricket academy in your city. Fortunately these days there is a cricket academy in most of the districts these days. If you don't have one, you can either shift your city or simply learn cricket via internet. There is a website called pitchvision.com which provides with each and every detail of how to play cricket. I am a semi professional cricketer and believe me; I trust this site more than my coach. The extra advantage of being in a cricket academy is that you will get plenty of match practises and if your coach is influential, he might help you in other ways as well. So I recommend you to join a cricket academy and learn the game via pitchvision as well. If you cannot afford to go to academy every day, stay in contact with the coach and ask for matches. He might be a bit reluctant towards you initially due to your age but once he realized that you have got something, he will start supporting you.
3rd- Tour different cities for matches: If you are willing to spend some money, then there are many tournaments (Corporate & Associate) are played every month. Get in touch with some clubs and attend their trials. If you get picked, you will be called in to play a tournament every month even some live tournaments on DD Sports. Some good people might spot you and your career will start skyrocketing.
4th- Play league matches in some major cities: There are semi professional leagues in cities like Mumbai, Delhi, Chennai, Kolkata, Lucknow, Kanpur etc. Get in touch with a club and they will call you for matches and if you are good enough, they will pay you as well. The advantage of playing in these leagues is that if you did well, you can attend district trial from the city and if you got picked for senior district tournament and you have done well there, you will find yourself in state team.
5th – Attend trials: BCCI and State associations organize various trials to find out talented youngsters. There are some special trials where a participant directly gets admission in National Cricket Academy. If you are lucky enough, you might end up being in NCA and soon in a State team. State associations organize trials for Ranji selection between March and July. Keep checking local newspaper for news on Ranji selection trials.
Now these are some major points you will have to take care of if you want to become a professional cricketer. Let's move on to some information on technical aspects of the game. You mentioned that you are a fast bowler so this is a plus point for you. These breeds are rare in India and remember, if you are in a trial and you are the quickest with a decent line and length, you will be the first choice of most selectors. If you can clock 130 kmh, you are among fastest bowlers in India at first class level. But 130 won't work. You have to reach 140+ to have any serious effect because that will make you different. Instead of elaborating about 'How to bowl fast' here, I will recommend you to read my article 'How to become a genuine fast bowler' in article section of this site. Also you can buy Ian Pont's 'Fast bowler's Bible' on Amazon. This is a great book for fast bowlers.