hrmmm ..
at one time I would have answered this differently with age of usually 25- not to my liking, but overtime .. I've had to do away with that.
Now, I look at maturity, personality, compatibility, and interests.

I would further ponder on whether it is possible to predict someone's age by their chat?
I don't think that you can predict age.. but depending on their posting style and reaction to things around them in a chat room, you can begin to judge maturity and much more.

a general age rule for me is 18+1 day. ( state law ) chuckles.