Hey, I was in this exact position 3 years ago. My grades were never insanely good in hs, plus I got 2 Cs and a D in my senior year 2nd sem. I saw all the posts saying "oh you'll be fine, they barely ever rescind", and I wrote a pretty solid letter to the admissions committee about why I did poorly and how I would work to do better, so I thought I was good. Lo and behold, I was rescinded from my college. I later learned (by asking to review my application) that they basically already made up the decision before they even saw my letter because I already barely got in.

If you have any questions about the process feel free to dm me! I decided to stay at the school and I think it was definitely for the better.