I am starting IT studies. As someone always interested in computers I have paths in my head how to get needed information. There is also a luxury of testing anything learn in practice by for ex. contributing to open source or creating a server.
Math was always interesting for me too, but I haven't spend time on learning it much, I have many lacks from middle school and there are topics I know about but can't use them in practice or have no intuition or forgot how to formally write them.
So I started to try to learn, as a self-learner most time I spend on Wikipedia and forums, but those turned out to be death end when it comes to understanding whole topic and not just reminding one thing.
So question to you that are learning math: how do you do so?
And I also never learned anything in a typical "school" way, I always need to feel interest or have a goal in something.
I'm also half-math and half-IT person. I'd recommend you to start Competitive Programming, try to participate in the contests, solve Codeforces (https://codeforces.com/?locale=en) or Kattis (https://open.kattis.com) tasks, grasp Asymptotic notation, etc.
Math (and academical) formalism is a thing, Wikipedia also shows it. You just need to get used to it.
What you will probably learn in the University:
I've always been more interested in discrete part of math where real numbers do not exist (only rational numbers do).
Alternatively, if you're as mad as me, you can try doing side projects, like creating your own Computer Algebra System or Ray tracing algorithm from scratch. It is a good brain exercise.
Go to your Campus library, look for some books. My University library was a goldmine for me. Take notes. If you have a genius idea, don't hesitate to talk with your lecturers or the Dean, they can offer you scientific work.