Hi Kavya,
After 2nd PUC a whole new world opens up for you. Just think of it as, you have no limit for what you can do. Sky is the limit. But since you have choosen science, you have got a back up option in case you fail in anything else. So what are you interested in? Engineering, Medical or the beautiful challenging field of pure science? Decide on this and I'll help you out on what you can do.

Good luck