Kris like I said in an earlier post with a little info you can " manage your sea time".
Lets start at the beginning.
There are 2 sorts of AET the Fastrack ( a very loose form of Artificer) caters for the more academically clever rating, you can be selected from your initial trade training at Sultan do circa 2 years in the fleet (air station) then return for LAET course ( 12 to 18 months I think ), then more fleet time and return to Sultan ( maybe RAF Cosford) for POAET`s course of soon to be 6 months. If not selected at initial training you can be Fastracked off LAET course( but selection from the field no longer exists at the moment). Thus you can get to POAET in circa 5 years.
Non Fastrack AET go through the process, but the process is slower for them as they compete with other non Fastrack AET`s for selection through appraisal.
Also there are 2 trades Mechanical and Avionics when you get to LAET level as an AET you do both (but there will probably be discussions to go back to 2 trades formally 3 trades)
Mechanical. Airframes(bodywork), engines transmissions, flying controls, undercarriage.
Avionics stuff with electramatricity. Radar, power supplies things that go Bang.
Thus in summary are you good at Maths/Science. When I did my Tiffy training in the mid to late 80`s it was like A level material but to an O level standard. I had done A level Maths Physics so thus it was piss easy for me.
My advice sign up for a Maths course at a local college, or try the open university, they do a range of maths courses, and a sort of test that identifies at what level you should start.
If your not mathematically minded still try AET you may find the Non Fastrack route is for you.