Um,
@123657 is wrong. The dvla guidance is 5 to drive. There is no upper limit.
So, you will need a provisional driving licence. There will be a bit on the form to fill in for that to complete about your diabetes. Then you will need to tell your driving instructor about your diabetes. And you will need to tell your car insurance about your diabetes - it won't increase the price, they just need to know.
Then you need to test before driving, and every two hours during driving (obvs you'll have to pull over to do the test). You cannot drive if under 4. If you are under 5 you should snack before driving.
When you pass your test and send off for the licence you will need to complete the dab1 form telling DVLA about your diabetes. If you have had more than 1 sever hypo in the last 12 month, no licence. If you don't have adequate hypo awareness, no licence. Otherwise, you will get a 3 year licence (everyone else gets 10 years) so that they can check on your control every 3 years to confirm you're still fine to drive.
Diabetes uk have info on this -
https://www.diabetes.org.uk/guide-to-diabetes/teens/me-and-my-diabetes/living-my-life/driving