I'll be the first to tell you I'm no expert by any means, but to me it sounds like you've been around a bow long enough to be able to make the switch to a new bow and release before deer season. My brother-in-law had never shot a bow before late this summer and I gave him my old Bear (which is too short for him) and he's already decent with it.

IMO, switching from fingers to a release should go pretty smooth for you. If you were going the other way around I would expect it to take longer to get used to it.

Also, I don't know about your state, but around here bow season is pretty long, so you should have plenty of time.