Dear

With this percentage you won't get good private university Because every good private university required Minimum 60 percentage in aggregate and pcm too.
If you are focused for Engineering degree then firstly re appear for 12th not only for good grade but for good foundation in Physics chemistry and Mathematics .

This foundation will help you for further education , knowledge and skills to learn advanced technology.

All the best

U may take admission in any good private college and do b-tech there ,like amity university ,Itm university etc