Reddit reviews Linear algebra and its applications

If I were you I'd look at picking up a decent book on Linear Algebra (not necessarily a textbook) and trying to learn from that. From there as long as you do your best to understand the material and do the exercises unassisted you should learn. Linear Algebra is a good starting point since for the most part you'll just rely on what you learned in high school to get started. Here's a link to a really good book if you're interested. Also, don't worry about how "good" you are at math or how long it takes you to learn new concepts. Everyone learns at a different rate and as long as you put the time and effort into studying you will progress.