You bet. A perfect starter bike (if this was 1991).
Dirt bikes lead a hard life. It takes constant and consistent maintenance to keep them RUNNING, let alone running well. Beside the RUNNING part, the stuff that bounces up and down is beat to death on a regular basis.
That said, if this is your first entry into the sport, there isn't a whole lot of sense in spending thousands of dollars on something you might have no use for this fall (resale on dirt bikes = HA!).
Your best bet is to take a riding buddy with you to check out the bike. He'll know how to check the suspension, headset bearings, wheel bearings, AND all the stuff scottyx said.
You can't expect 'mint condition' to apply to something like a 12 year old dirt bike (well, unless you buy it from dan (acutemp on this forum) ), but it IS possible to buy something other than a complete POS.
Good Luck!