I think that you are doing very well.
I think that your in-state public schools are great choices. I am not familiar with what specifically you need to do to get your desired major at UT Austin. However, it is hard to imagine a stronger student somehow taking your place.
For a potential CS/AI major, I would recommend that you also keep up in math (which might be sort of like telling a fish to keep swimming – it looks like something that already is you). Both math and CS are very relevant in AI. Things like probability and statistics, calculus, and linear algebra are going to be relevant. Some algorithms courses will too, but will also be part of a CS major.
I got my master’s degree at Stanford in a subfield of applied math. The other students in the program had come from a huge range of undergraduate schools. I am pretty sure that the large majority came from schools that were lower ranked than UT Austin (which of course covers a lot of schools). There are not a lot of secrets of mathematics that MIT or Stanford are going to teach an undergraduate student that you couldn’t have learned at 50 or 100 other universities. Something like a bachelor’s degree at UT Austin or at T.A&M plus a master’s at Stanford might be less expensive compared to just getting a bachelor’s degree at Stanford or MIT, and also would give you at least some experience at two different very good universities, and would get you a very good master’s degree. Of course MIT and Stanford are reaches for pretty nearly any student.
By the way, the overlap between math/cs and music is also something that I have seen multiple times. Working in high tech and liking music, I have on several occasions gone to a music event and seen someone I know from high tech get up on stage and play, and mostly play very well.
I think that you are competitive at any university in the US, and probably any university in the world that teaches in a language that you speak. The real questions might be whether there are any universities in the world at all that would be a better fit for you, and whether the top ranked universities in the US would be worth the cost. Neither is obvious to me one way or the other. Also, being competitive for admissions does not make admissions likely at the tiny, tiny handful of schools that would be as strong as UT Austin for CS or math.
Between CS, AI, machine learning, and applied math, you can take a bit of each and decide on a major well after you start university (although different universities vary in terms of how hard it is to switch majors). You could most likely get a bachelor’s degree in one of them, and a master’s degree in another of these same fields. If you want to apply this in the medical field, then you will most likely want to also take some other presumably biology/chemistry/biochemistry related courses (which gets into an area that I do not know well). However, you can start doing this as a freshman in university, and decide over time whether this makes sense to continue.
And I think that you are doing very well.