Does he want this for himself or is he caught up in his classmates talking about it? If everyone around him is excited about learning, he might just want to learn to feel part of the crowd?
Is there a cost to your driver's ed? If so, you can stall while he earns the money to pay for it (extra chores to show his growing responsibility to handle driving)?
You do know him best. You might want to go to the library and borrow a driver's ed manual (or purchase from department of transportation) and let him look through what the class will cover. You two can then decide if he is ready then?
Good luck!
