age limit

[Cust0ms]

hello
I would like to add few new functions to my forum.

1. When user is want to register first see page where must select a date of birth (and next normal register process like nick, password etc.).

2. User can not change a date of birth.

3. I want to add 'age limit' for few forums (user can not view forum if doesn't xx years old).

I hope that was understood.
Thanks