Sprint distance or Olympic distance

With 9 months of training there is no reason why you couldn't do a oly especially if you're already pretty fit.

The hardest part to me about an oly is the swim, just make sure you can swim a mile and it should be no problem.

I'm 22 and I just started training not very long ago. I'm actually training for an olympic in may to get my feet wet in triathlons, and a HIM in august. I will be doing some other runs and rides in between, but those are the main 2 I am specifically training for. 

Right now i'm just getting back in shape, only working out for 6-8 hours per week. I will be gradually increasing my workouts until December when I am going to start training for the HIM, increasing my training to about 12-15 hours per week. I will be doing my first IM during the 2014 season unless for some unforeseeable reason I have the ability and opportunity to do an IM before then. Louisville next year would be cool, and I'll probably pay the entry fee if it isn't sold out by sometime in March.

I don't know your specific situation, but it is a lot easier to get to that level if you've been there or close before. If you've never had that athletic ability before it will take much longer to get there.

My thought is figure out where you want to end up and train for that, but taper into that training regimen. If you want to train for a full IM, then taper into a full IM workout. Don't just jump strait into it or you will hurt yourself.

If you have 9 months and are already in good shape, you could easily pull off a sprint Tri in the spring and work into an Olympic later in the year.  Heck, by the time your sprint would come up, you could probably have completed a few "mock tri's".  We do mock tris here once a month.  Just a group of us get together and either swim at the Y or lake, ride stationary bike or outside, and run on the treadmill or out side.  Some combonation of these or all three. 

The best part of a sprint tri is that it is over fast.  They can be very hard depending on how hard you push yourself but if you casually go through the event, a sprint can be rather easy too. 

I love doing sprints because I push hard through them from start to finish.  It also helps me work on my transitions too. 

With 9 months ahead you can do either, if you aren't already there!

On the olympic distance you have to think about hydration, the sprint is sufficiently short that you can (almost) rely on what they hand out on the run.

Also, the longer the distance the more you have to think about doing your race and not getting psyched about somebody passing you or setting a chase on whoever is right in front. That makes the sprint fun, and the olympic hard.

Regardless, in your first races there's a lot of things to learn, placing yourself for the start on the swim, sighting, the transition, mounting and unmounting on the bike. You'll learn on either distance, but don't take your first races too seriously, something's gonna mess up.