Can I marry my second cousin from Kerala

Your grandfather's brother is also grandfather to you. His son will be your uncle and his daughter will be your sister. So in many religions, these marriages are not allowed. As per the Sapinda act also your marriage is not acceptable. Is such marriages are allowed in your community and are there any examples where such marriages are performed. Sapinda marriages are accepted when such marriages are permitted by valid custom or usage. The custom should be a valid custom as per Section 3 of the Act. Otherwise, it will become punishable if anyone complains about the same if not today even tomorrow.
You can contact a good lawyer who can tell you the consequences of such a marriage. If your parents and their parents accept, she can be adopted by any distant relative of yours and once the adoption is registered you can marry her without any problems. Anyhow lawyer's suggestion is required for this. But going for marriage without the consent of parents may get into legal troubles.

While analysing your case, both of you have the relationship of brother and sister and such marriage are prohibited in our societies mostly except in some pockets such marriages are allowed violating the sapinda relationship. It would rather depend upon the system of your society and despite this take the help of a noted lawyer in resolving your case.
The second aspect in such a relationship is that there might be the development of some genetical disorder which could be noticed in your off- springs after their births. If you come across such an abnormal situation, it will disturb your mental peace apart from huge medical expenses. Hence, it would be better on your part to take the opinion of a specialist dealing with genetics.
The third one and to my opinion it is the most vital in your relationship is that you must judge your partner in respect of her mental stability, her reliability and her cooperation in majority of issues. This needs to have a constant companionship for at least six months to be familiar with her true personality.
Take every aspect in consideration before finalising the deal.