Yes. It's excellent at the range it's focused on. One of the best. However, it is very narrowly focused and doesn't address weapons or grappling (typically).
Impossible to say. First you must define "proficient." Even then, it's not really possible to say because a lot of it depends on the practitioner, his aptitude, the coach & partners, and how much time the practitioner can devote.
Sure. You'll probably be sparring well before then. As far as winning a match, it depends on who you are facing. If you're talking about an actual match in the ring (as opposed to a regular sparring session with your teammates for training purposes), your coach should be trying to find you an opponent around your own experience level so you can have a fair fight.
If you want to catch up with someone who has more experience than you, you'll need to train significantly harder than he is or train more consistently than he is or have better coaching than he has or be more naturally talented than he is or some combination of all of those.
Still not enough info to say. Too many variables.
