I am only rushing, because you have to have an end game character to have one of the new classes. Something i wish they explained sooner.

1. Do I really need to waste time with "gathering" and crafting? or can I wait till i reach 50 at least?

The whole "change your suit" for crafting and gathering was a little annoying so I didn't mess with it much.

2. Crafting is mandatory to improve your gear with materia?