I am 13 and I am getting into the sport also. I ahve a '94 V-Max and it runs great. Only thing I have to complain about is the stiff suspension (Take into account I am only 110 pounds), and the hand grip warmers are eather a little too toasty or too cold. Great sled overall.
Personally would get a Polaris or Ski-Doo if getting an older sled, and try to get one around 2000 or so. Had a 95 Polaris Indy 500 and that thing was a tank but still prefer something closer to 2000 or beyond.
I owned a 94 vmax 600 for 4 years. I picked it up for a spare and sold it last year. It ran fine, but it smoked alot. I found out that was a problem with those yamaha's over those years. Not a big problem to replace the pump, but it got good mileage (100 miles to the tank) and I could plow powder until you had to stand up to see over the wind shield. It always started up hard if it was left to sit for more than a week...not sure why. But once it got started it ran fine and started easily. I like the very stable ride with the outward possitioned pogs and I think that it beat the heck out of the stupid trailing arms that they went back to. Obviously they were ahead of their times with the poggo shocks, as the trailing arm is all but extinct by all manufacturers today.
It was a good bullet proof sled that I would buy again escpecially if it only costs $900 froggy dollars. I would change out the coolant tho and check the hoses for cracking. Like any old sled you need to go all thru it before heading for the hills.