Andy,
Confidence is the key with anything like this. It takes aptitude, situational awareness and lots of concentration. However, no one will expect you to have all of that the first time you step into an aircraft.
RT (Radio Telephony) does get a little getting used to. I've been an air traffic controller for 7 years and recently completed my PPL, it did give me a massive advantage as all the 'lingo' came naturally. But i remember the first time at the school when I was given CAP413 and my head almost exploded. The key? Practice. Which is what you will get as you progress on your PPL and your instructor explains it all to you, eventually you'll find it coming naturally and you'll think back to this topic when you thought you'd have issues.
As the other lads have said, go for it! And go and enjoy a trial lesson. Also shop around for prices on your PPL and never pay all as a package upfront!
Best of luck with it
