For MIT, I do not think so.
I remember as a freshman at MIT meeting one student who had only been 7th in their high school class. This was however at a high school that is famous for being very rigorous and very good for math and science, and that has about 500 graduates each year. Thus he was not in the top 1%, but was in the top 2%. I knew another freshman who had been 4th in a class of about 200, which again is just top 2%.
For you, “A’s in everything” for math is good, and is typical of what you would see for a student headed to MIT. However, I also see two semester B’s in science classes. This again suggests that you are doing very well, but not quite at the level that makes me think that MIT would be likely for admissions.
MIT is also a very tough school once you get there. Classes go fast. There is tons of homework. Exams are tough. This is a school where you really need to want to work very hard to enjoy (or even survive) your 4 years there.
I am sorry to be a bit discouraging. I think that you are doing very well. I am not convinced that MIT would be the best fit for you. That is okay. There are a lot of other universities that are very good and that would be a good fit for you.
A student’s major has a significant impact on what they end up doing with their career. This does indeed have an impact on how much money they make. However, it also has a big impact on what you end up doing on a day to day basis for much of your life. I really think that you need to do something that you like.
Having no idea what you want to do with your life at this point is very normal. One daughter when she was in high school came to me quite concerned that she similarly had no idea what she wanted to do with her life, while her friends all did know what they wanted to do. I pointed out that yes her friends did know what they wanted to do, but in six months they will want to do something else, then in the end they will probably end up doing something different again. This particular daughter did not know what she wanted to do until she ended up in multiple lab courses in university. She discovered that she loves lab work and is very good at it. She is currently getting a PhD in a biomedical field. She had no idea that this might be the right path for her until sophomore year of university, and did not fully decide to take this path until after graduating university and doing a research job for a while. Getting quite a bit of lab experience in university helped her a lot to pick the right path, but this is something that you can get after arriving at any one of a huge number of very good universities. Of course internships can also help, and will also be available after you get to university. Sometimes some of these opportunities are good to help you identify something that you do NOT want to do, which again is part of finding the right path.
At the point that I graduated university, with a bachelor’s degree in mathematics, I still had no idea what I wanted to do with my life. I tried a bit of this and a bit of that and eventually figured it out. This is pretty common. We might decide to do different things, but trying a few things before settling on a career is normal.
All of this however is probably more likely to come out well if you select a major that you like an are good at, and that has at least some practical application.
Having a “big salary” is a mixed blessing. No one is going to give you a high salary out of the goodness of their heart. They will expect something in return. Stress and long work hours are sometimes associated with big salaries. High expectations to put a lot of effort into things and succeed at something that is hard is often associated with a high salary. This of course is easier to pull off if you are doing something that you like and something that you are good at.
Whether to go for a PhD is something that you can decide way in the future. It is typical for admissions to PhD programs to be insanely competitive, but for a PhD to be fully funded. What this typically means is that the university pays for your tuition and fees, pays for your health insurance, and gives you a stipend that is just enough to live on and cover required books or other incidentals. The good news, if you can get accepted at all, is that it is a very good free education. The bad news is that it takes multiple years (6 or 7 years is not unusual) and represents a big postponement of all of (i) getting a high salary; (ii) saving for things like buying a home; and (iii) saving for retirement. Some modest financial help from parents can make this marathon less onerous, but is not really needed. Having significant financial resources to back up your PhD studies might be one of the few things that is not really needed. This is however something to either think about way in the future, or to just not think about at all (a PhD is definitely not for everyone, and not for most people).
I got a master’s degree in a subfield of applied math at Stanford. The other students in the same program had come from a HUGE range of different undergraduate schools. There was only one case that I knew of where more than 1 student had come from the same undergraduate university, it was probably a coincidence, and it was NOT ranked in the top 50 in the US. This wide variety in terms of where graduate students come from is of course typical for most highly ranked graduate programs across a wide range of fields.
Getting a bachelor’s degree from TA&M, or UT Austin, or any one of a wide range of other universities, would not stop a student from getting into a highly ranked graduate program. Doing very well as an undergraduate student, getting good internships and/or research experience, and optionally getting some work experience after getting a bachelor’s before applying to graduate programs, can also help a student’s chances to attend a very good graduate program whether in a subfield of math or in something else.
And @supernova61 you are asking good questions, thinking about the right things, and getting some good advice. This is just part of figuring out what you want to do. This will take some time and thought, and will probably involve some missteps or changes in direction, but that is okay. You are doing well and I expect that you will figure this out over time.