Marine,
I did a tour there at the same age. Changed my life forever. Completely changed me as a person, you think you grew up fast joining the military. Just wait. No going to tell you either way what to do, its not my place. But something to think about, you do a tour now or later. Either way you are going to change. Ive seen a lot of relationships end not only because of the tour, but because how different we are when we return home. So it may be in the best interest to do one now. That way upon returning your significant other will be able to handle you as a new person. Not trying to sound depressing, a lot of relationships are strengthened by tours. But just another aspect us in the military have to deal with. The choice is truely yours, You probably already knew the answer to your question way ahead of posting it. You just didnt know it yet.
The draft still exists. It just goes by a different name. Individual Augmentation. Basically all service members in the Air Force and Navy has a little blurb in their contracts that states in a time of need a sailor or airmen can be chosen to be sent to the Army to support them. Currently there are a few thousand sailors that are filling this role in Iraq and afghanistan. Biggest difference from keeping it a true draft is it does not effect civilians. Each command is given a number of sailors they need to give to the program every so often and usually the spots are filled by volunteers. Im some cases a sailor is randomly picked to go. In my case I was picked. Trust me, being in the Navy for all of a year and unexpectedly handed orders that said afghanistan was a moment where Im not afraid to say I almost pooped my pants. But in the end it was well worth the experience minus a few life long side effects. Sailors sent to fill these slots are first sent to Army bases and given a condensed version of Army basic, then sent to training for their specific jobs they will be doing overseas. Jobs differ from EOD, Detainee Opertions, PRT Teams, Convoys, etc. Basically almost any job the Army has Sailors are trained to fill in.