I know quite a few between the ages of 5-20 (i.e. school/uni age) - off the top of my head I can think of 8 in our primary school alone, and 5 in either 1st/2nd year at secondary age (not all the same school), and then 4 17-20 age (i.e. School leavers/uni age)
I think that most are spelled Aiden but I do know a couple are definitely Aidan and there are some I don't know the spelling of.
I'm in NE Scotland