Is this a bad idea?

[SunsetOvrC@aol.com]

After several years riding a totally mental horse I decided to look for a 
calm one.  I am looking at this nice Appy who is good in all respects except 
for one, his age.  This horse is 13.  I am wondering if it is fair to this 
horse to compete him.  What is the average age for retirement of an endurance 
horse?  Keep in mind, my number one aim for now is to have FUN.  If he 
happens to excell, that will be great, but my goal for now is just to finish.