The RN is certainly on a recruitment surge for pilots due to the shortfalls in manning on their Harrier Sqns & if you fit the criteria for fast jets, you'll end up on the GR9.
The RAF has a wider diversion of types & as a result, there is no guarantee on which, if any, fast jet you will end up on.
From an academic point of view, a degree is not mandatory. The RAF does try to recruit a mixture of graduates and sixth formers. Those who come into the RAF at 18 offer a potentially greater pay back, in terms of years served, than those coming in at 23 after university. Either way, it's a difficult road that will require absolute dedication & sacrifice from you in order to get through flying training.
If you want it, get stuck in and pop into an Armed Forces Career Office with your list of questions.
Good luck.