If you've access to a car, and someone who's happy to supervise you, try reinforcing what you've recently learned with private practice.
The other person must be over 21 and have held a full licence for 3 years. The car must be insured. You'll need a good working relationship if you feel pressure on the move !
The person must be able to give clear instructions (such as "Take the next road right"; "At the roundabout, go ahead - that's the 2nd exit"). They should keep calm, and give only constructive criticism.
This RoSPA guide may help teenagers learning with parents.