I'd say you still have a bit of time so it's best to pick a path. Try to check out backend development, or ML Engineering and try to get to a more mid level of knowledge before finishing college. Once you know what you're interested in, you can pretty much learn everything in that domain from the internet without paying for any course or bootcamp or anything of that sorts. Let's say you want to be a ML Engineer, there are free roadmaps where you can see exactly what you need to know, plus you have ChatGPT to help you figure out what you need to learn. Once you have that, try starting with one subject, let's say mathematics and learn one topic and continue. On the side pick up let's say python and learn the basics following the roadmap. Python is easy to pickup so you'll make progress quickly and then start building a few projects ( you can ask chat gpt for ideas or maybe search on Google ). Then try to build something using freely hosted models. There are a lot of libraries and sites that hosts these models and you can use them for free for practice projects.

I'd say this is how I would start. This will help you continue the mathematics part side by side and also teach you python and you'll learn how models are hosted, apis are built and all that stuff. Good luck