I'm a guy, no one knows my age, should I celebrate my 30th birthday?

Do what feels best for you but, I personally think that 30 is a great age and it is also a milestone in everyone life...I say CELEBRATE IT! If you look great at 30, you should embrace it, don't be embarrassed by it; the people you hang with will probably wish they could look as good as you at 30 years old. I'm 32 and when I turned 30 I had a blast with all my friends.