Questioning my decision to attend

Honestly, I have been surprised by college results, but after I just graduated I feel excited about college. However, I kinda feel scared, and now I think I should have SIR to another school (Cal Poly SLO, UCSB). Honestly I committed to UC Berkeley because of the independence and strong academics especially for my department, now I think I can’t handle it. I know I made similar posts, but now I still weird. The other people at my school going to Cal are MUCH smarter than me. My GPA isn’t that strong, and I have gotten ALL B’s in science and a few math courses (including AP Chem, AP Physics 1), and I only got a 3 on AP chem and 720 on SAT chem. My math is decent though (750 sat2, 800 sat math, 5 calc AB) but it is still hard. My SAT score (1490) is pretty good, however, but I spent a lot of money of extensive coaching, and even took the SAT 4 times (my last time was 1390) and ACT 3 times. Most people I know get like 1560/35 on their 1st try, without classes.
My EC’s are decent though, as I had a few small awards and officer positions, and my essays were a bit mediocre. I also applied to a less competitive major within engineering (like 8% acceptance rate overall), my major was probably like 15-20%.So, I definitely am not as qualified as most others at Cal, especially considering I am in engineering.
I also have to take a lot of Physics, which I am not that good at considering I probably failed the Physics 1 AP exam this year, and the class is really hard for me (and that’s only physics 1!). There’s also a lot of grade deflation at Cal, so my GPA will suffer SEVERELY.
I know many of you guys are gonna say: You got in for a reason or You deserve to be a Berkeley or With hard work you can still succeed.
I understand that it may be very hard for me to adapt to college and the hard rigors of engineering, especially at a top engineering school. I hear many horror stories of smart people doing bad, and even my really smart friend last year (ranked 3, had 35 ACT, 4.5+ GPA) end up with a sub 3.0 GPA this year. I feel like for me, the situation will be a lot worse.
Anyways, I will try my best to be prepared, but I am still really scared.

Post edited for clarification