You have to be 20 unless you have had any previous cadet service therefore you may join when you are 18 upon leaving the organisation as a cadet - LASER Review 2005
Do you have a weblink for that at all?
Just that when I was a CI (not very long ago), you had to be 20 regardless.
I'm curious because a friend of mine (ex ATC), whos 18 wants to be a CI, and has been told to come back when she's 20.
Our old CO is not being very helpful.
Cheers.