What shall I know before starting vectors and matrices? (Idk calculus but I know trigonometry)
You should know algebra(...)and it really depends on the person. I would suggest finding that topic on khanacademy, watching the vids, then going back if you have trouble.
here Let me send you the links(you don't have to go in them.... It's fine..)(and also, don't freak out cuz it says precalc, It's just the label... I learned this before algebra1 so the labels are kinda off sometimes...):
Matrices: https://www.khanacademy.org/math/precalculus/precalc-matrices
Vectors: https://www.khanacademy.org/math/precalculus/vectors-precalc
Yes! i use khanacademy! , Lol I already freaked out when i saw "Pre-calculus" :DD
I know... But the weird thing is, Precalculus varies from people..... Some think it starts when you learn sigma, others matrices..... I think it's just Khanacademy's thoughts.