How bad must your senior year grades be for a college to revoke your acceptance?

I'm rather concerned that my college will revoke my acceptance. I have been admitted and enrolled to UNC Charlotte, and have also been accepted into their School of Architecture, which accepts no more than 52 applicants out of over 300. As much as I begged my high school counselor to switch up my schedule, I ended up having all electives first semester and all core classes second semester of my senior year. Needless to say, I had no problem with first semester, all A's and one C (in precalc, so I guess it wasn't ALL electives, but close). My second semester I made C's straight across the board, but I had three honors classes and an AP, which was a huge workload for me. My grades have always been rather average, but my SAT and ACT scores were outstanding, which is what I think actually got me into the School of Architecture haha. But I was wondering, I'm about to send my final transcript in, do you think that they might revoke my acceptance? I feel like they might if I declared my major as undecided, but since I've been accepted into the most prestigious School at the university (which requires us to spend HUGE amounts of money on laptops, drafting supplies, CAD programs, etc.), there's a better chance that they would not revoke my acceptance. Does anyone have anything to share on this? Thanks!