Answer 1

It's difficult to measure your knowledge. Probably just start and see if you can keep up ;) However, advanced math is needed. Linear algebra, matrices, calculus, statistics, probability, optimization.

Answer 2

I just started learning ml and this is what I think, I have basic knowledge of python. You need to learn some modules like pandas, matplotlib, numpy. Once you started you will learn libs like scikit, tensor.
You also need basic knowledge of statistics, probability and algebra

Answer 3

I agree, I started out with about the same experience as you and I'd say start smaller - maybe a project on image identification, or even a chat bot, and work up from there to something more in-depth.