I was a math major who took quite a bit of computer science courses in university. I do not think that you should be focusing on UCLA and UC Berkeley. Top schools do not have any mathematical secrets that they are going to teach undergraduate students. You can get a very good education at any one of a very long list of universities.
Also, you do not need to rush to graduate quickly. When I was in graduate school the other students there were of a rather wide range of ages – many and probably most of them had several years of work experience which of course meant they were a bit older. This is very common on university campuses.
Slow down. Take this calmly and understand that life is not a race.