Science

Hi,
PCB does have a vast scope. All you need to do is, you should try and understand what exactly your FORTE is.
You can do a B.Sc, B.Com, BA, Business Management, in short what I want to say is, being an average student never stops you from taking a degree, except for the ones where Maths is compulsory (as you have taken PCB).
Class 12th matters a lot, but what actually matters in the end is your Master's Degree, your specialization. You can do Science and shift to various streams. The ocean is big, try diving near your goal.

For B.Tech, you must have to clear JEE Mains and Advanced both for getting government colleges or you can also give CET. CET (Common Entrance Test) is a state level exam conducted by all states now. For Maharashtra, you must take MHT-CET, for Karnataka there is KCET. Every state conducts their own CET.
For more information, you can google this.
But for B.Sc no extra exam. It's just normal. Just get good marks in class 12th.