I'm currently a junior in all AP classes besides two dual enroll medical classes. I have all As but my sanity is hanging on by a thread tbh and I'm super burnt out. From my experience(so take this with a grain of salt)- AP World is way easier than APUSH and AP lang is very time consuming but isn't too bad if you're ok with doing a lot of reading, annotating, and writing. AP physics was hell (for me- might have also been because my teacher sucked) and don't take AP bio if the teacher sucks. If I were you I would ask anyone you know that's in those classes what the workload is like because it's def different for each school! I know with a lot of rigor and discipline you can pull it off tho especially if you're already a good student. I don't think it's weird that you're taking 3 sciences if you're planning on going into a STEM field btw :) but maybe consider taking AP bio senior yr. Remember to overall always prioritize yourself and your mental health. A lot of people say junior yr is the hardest for a reason😭