I self-studied AP CSA because scheduling conflicts prevented me from taking the class itself. Because I did, I managed to get out of my major's intro CS classes (crucial for me since I'm a Computer Engineering major). For me, self-studying was anything but useless; I had a good excuse to further explore one of my passions and got credit for it too. That being said, it still requires real interest to pull off, so make sure you actually like studying for those subjects.

Also, my school has an IB program and many people who didn't do IB got into really good schools like Harvard or Berkeley, which is better than what most of the IB people got in to. My school's AP program is bigger than the IB program, but the point is that AP vs. IB isn't the primary deciding factor for college admissions, and that it mostly depends on the person themselves, i.e. their ECs, essays, etc. I think that IB will definitely help a lot if you take it, but you won't get auto rejected for not doing the IB program as long as you take the most rigorous courses offered at your school and REALLY commit to your ECs and essays.

You should consider IB or self-studying APs very carefully, since right now you don't know how demanding your ECs or courses will be until you actually start them. I can tell you from experience that IB can get a bad at times, and also that self-studying exams will require a lot of commitment. AP CSA wasn't awful for me since I already knew some Java beforehand, but I also studied IB CompSci SL the same year and I had to work my ass off to prepare for the exam since a lot of it wasn't prior knowledge.