Personally I didn't like knowing my online friends ages, because some people can't help how they feel.
A mate told me he was 12 when I was about 15, it was fine, added him on msn and I saw his display picture and he was a very young looking 12 year old.
The way he spoke in my mind entirely changed, instead of perceiving his messages how I wanted for the better, they went in a different direction.
Try and repair the friendship man, don't over do it but don't not try.