Is it uncommon to get a drivers permit at 21 years old?

I got my permit at 15 and a half. Got my license at 16. Now at 21, I can't possibly see myself not driving. You're a bit of a late bloomer

Not at all. Many young people are waiting later for various reasons now such as yours. In the 70 s when I grew up it was not common to wait but a few did. My parents said "you are not going to wait so we don t have to take you everywhere." My Mom actually took off work the same day I could get my license to take me to the DMV. With in car and classroom driver s education I didn t have to take an in car test.

I got my full licence at 18 as did lots of my mates - we're in the UK.

very uncommon to wait that long