Hello all, I’m a current Senior and the school year has just started. I’ve been in AP Calc Ab for two days now and am having second thoughts about picking the lower level, since I plan on studying science or engineering in college. I’m currently taking 4 APs(Calc,Physics 1,Lit, and Bio.) I would naturally have selected BC, but Im afraid my math skills still need to develop, perhaps not to the level, but to the speed of BC. Should I go for BC because it will give me a better edge on Apps in comparison to AB? In total, my APs add up to 9, the others being Capstone,Human Geo, Chemistry, US history, and Language. How much of a disadvantage would taking AB put me at? Any insight is appreciated, thanks!
I have the same question regarding my son who’s a junior in high school. AB or BC ?
He can probably take AB now and then BC senior year.
Depends upon how the school sets up AB and BC.
Back to the original question, there is no one-size-fits-all answer. It will depend on context - your total schedule vs. the schedule of other students from the same HS applying to the same college. It also depends on the tier of colleges. I don’t think that a single course will be a make-or-break No college requires BC, but really tippy top STEM colleges may wonder why BC was not chosen where offered. But if the pace of BC is a concern, you are only one year away from where every class will be at that pace. Keep in mind though that an A in AB is better than a B in BC. Also every college, and I mean every single one, offers a Calc 2 class which will have freshman STEM students in it,
Math is a cumulative subject. If you are at the level where AB is appropriate for goodness sake don’t try to take a more advanced class! An “A” in AB looks better than a “B” in BC. 
Colleges want to see that you’ve pushed yourself AND done well. And when you get to your college courses you will be better off with a really solid high school math foundation. Top-tier colleges are more than happy to teach Calculus to their STEM major freshmen.
A student who reaches calculus as a junior should be a top student in math, so if the BC course is suitable for students who have just finished precalculus, a junior who did well in precalculus should be able to handle BC easily.
However, if the student struggled in precalculus, suggesting that s/he was inappropriately accelerated in math starting in middle school, then the slower paced AB may be more appropriate.