ChrisH:
I bought a bow in Sept. of '05......around the time of our season opener. Actually.....I had no idea WHEN our season opener was. I didn't even intend to hunt deer with it. The learning curve for becoming proficient with a bow is a short one in my opinion. The learning curve for knowing when NOT to shoot is one that I think I "might" have a good grasp on......after sighting 400+ deer from stand in my 2 seasons.
Do I think you can become proficient is a short time and take deer...this season? Yes. Do I think it's a slam-dunk? Nope. I think you need to shoot a LOT.....and ask the guys on your team and the forum for a lot of help.
Biggest piece of advice I can give you is.......(and this is usually wrought from experience

).......
Think about the path your arrow will take THROUGH the animal. There is no "set" great spot to hit a deer. You'll hear a lot of guys say "Aim for the exit hole". That's sound advice. Remember this.....and you'll be ahead of some. I won't preach ethics to you.....but I'd just ask as a fellow hunter that you be realistic with your range.
Heck....no there isn't an experience level requirement for the contest. Not sure I would have taken the path you did.....but there's no reason you can't help your team.
Good luck.