I'm going to look at a 14 year old next week and the age isn't even the slightest concern. One of my favorite horses to ride had been a 26-28 year old. He was fun and had tons of life. I was told by my friend who owned him that he passed away this past summer in his mid 30s.
If he looks good and is sound I would have no hesitation.
My mom got an 18 year old pinto gelding at a meat auction when I was in 5th grade. Her friends laughed because she paid 800 for him (had to outbid the meat buyer). Found out at my first show with him he was a well known and accomplished show gelding (judge was floored when she found out where we got him). I won tons with him and we trail rode him all over Oregon until I left home for the Navy after graduating from high school. Best horse we ever had, and he lived to 38.
Aw that's a great story!
We only have a pic of his head....:(
We have a gelding that we were roping calves on at 26! He loved his job, but we retired him and he is now happily teaching kids to rope at brandings :) but it a all depends on how the horse has been taken care of. Try to get as much background info as you can and of course a vet check!!