UPDATE: Thank you to everyone who participated. It was fun to see everyone's guesses come in. No one actually got it, I think because of a psychological fear of nice round numbers. The correct answer is 30.
It's not a secret, but some people have asked how old I am. I thought I would have a little fun and let people guess for a few days before I say. There is no prize, but hey, if you get it right you can feel good that you are able to accurately guess people's ages (at least mine). : )