Curious - how can you surmise age from writing style? I've never heard that before (except perhaps for people so young they haven't finished school yet).
Would you care to take a shot at mine?
Theres definitely nothing scientific about it, it's just sort of subconscious and clearly not accurate, I guess when you have been using forums for 17 years you tend to characterize people by the style they write, based on how laid back they sound, or if their writing insinuates their energetic in getting their point across, if they sound ranty, or if they come across with good general knowledge in their post's. I dunno about yourself, I'd probably peg you at mid 30's +, you sound pretty mature.