I did Strang's linear algebra course[0] (link goes to Youtube playlist of lectures) several years after graduating and recommend it highly. I was looking for refresher but I gained a deeper understanding of several important concepts; in particular it's fair to say I barely understood, or perhaps even misunderstood, SVD until Strang. If you're not sure if you need something like that, I suggest doing something like testing yourself on this video[1] or the MIT problem sets[2] it's easy to tell yourself that you "know" linear algebra when it would be closer to the truth to say that you used to know linear algebra, but can't answer even basic questions today. After Strang, Golub's book on Matrix Computations is also really incredible.[3]

[0]: https://www.youtube.com/watch?v=ZK3O402wf1c&list=PL49CF3715C...

[1]: https://www.youtube.com/watch?v=Cll03FUxjuk

[2]: https://ocw.mit.edu/courses/mathematics/18-650-statistics-fo...

[3]: https://www.amazon.com/Computations-Hopkins-Studies-Mathemat...