Welcome!!
First of all If you want to improve your 12th marks then its ok go and try for improvement. Otherwise try to analyse and recognize your field of interest which will let you to move on desired path accordingly. Having a poor score in 12th doesn't mean to an end, it was just a poor start.
With reference to your interest in electrical and electronics, you can join any of good private colleges for pursuing btech. Working in one's own field of interest can uplift you for the lifetime.
Good luck and have a nice day!!
Feel free to ask anything :p