Theo, 19, who earns £30,000 a week, said he'd rather keep his Golf than buy the Audi R8 of his dreams because he doesn't feel he deserves it yet.
The Arsenal star said: "I saw it a year ago and thought, this isn't the right time. I've got to establish myself first."
Theo won't be falling for the usual footballers' vices of gambling and women either.
"I just want to reach the top of my level without any distractions," he says. "For me, it's not about that - it's about playing football.
"When you get your first pay cheque you go out and spend, spend, spend, but the best thing is to start saving money for after football."