Hi mate.
Knowing how to drive a car & knowing how to drive a car to test standard are two different things.

If you know all the basics & you're good at picking things up then providing you've got a good instructor it shouldn't take you too long, as Dojj said getting a test booked is what can take a while (it's anything up to 10 weeks waiting time at the moment depending on where you're taking your test)

Have you got any lessons booked with an instructor yet mate?