What do I need to learn before learning Calculus?

the students who struggle in calculus are the ones without a solid algebra background. there will be a lot of algebraic techniques applied. also make sure you have a good knowledge of trigonometry (mostly the trig identities) as well as the number e and logarithms. you will use all of these extensively.

That sounds like a good plan if you are rusty with algebra.

Yes,
start from Alg1 , 2 , ...