The way the air force works is as described with aircrew steadily progressing from one type to another or sideways to staff jobs.
This is in contrast to some civil operators where they see no economic benefit in training old pilots to a new aircraft and also training new pilots to replace them on the old type. They simply dump the one and recruit the other, which was what happened when Heavylift binned the Belslow.
Right now, at 21, the OP is definitely in between. Unlikely that he would be streamed Tornado (?) and too soon for Lightning so there is really only one FJ option.