Yes exactly, CCF can recruit from Y7 but as I said above, you have to leave at 31 Aug of the year you leave school (assumed to be 31 Aug after your 18th birthday).
@daws1159 any CCF(RAF) unit not issuing or wearing blues should be picked up on inspection and given ‘words of advice’ at least - this is a core requirement. CTT SNCO should be on the case. Though some are intransigent, I admit.
Actually the new OC RN section here asked me for advice on how to rejuvenate the section, as he was very aware that the RAF section has much the best record in retaining cadets after their compulsory 1yr service; one of my top things was to wear blues as much as possible so the section is visibly different, and he’s done so. Only wear combats if you expect to get muddy!