Yes, Moderators can enter full rooms.
There can be many reasons you don't get chosen to become a Moderator.
Yes, You need to be older then 12.
You can talk with them through the Call For Help.
A Moderator will have a special 'ADMIN' badge and they will
always show it when asked. Don't fall for impersonators, always
ask to see their badge. Do not fall for impersonators without a badge.