hello i have a interesting extension request

hello i run a forum for people that are incontinent but i guess for some it can be other things. i was wondering if you could make a extension that offers age restriction to categories, and topics. or a extension that when a person registers it asks their age and then depending on the age it can put them in the appropriate group i don't really want to maintain two forums that basically the samething so i would like a age restriction as i i was saying if it possible. thank you.