Dont try to run before you can walk....Believe me when I say no matter how old you are, its experience that counts. You say you will drive like an old duffer until you feel confident about the car, buts whats to say you wont get too confident? Thats when accidents happen when you dont know your limits. There will be times when you will put your foot down thinking that you can make an overtaking manouver or not realise your speed and not leave enough braking distance or take a bend too fast. And then there are other drivers who will try and goad you into racing or when the red mists sets in, will you be able to get yourself out of trouble? Theres a high risk that youll damage your car due to lack of driving experience, if you are willing to risk damaging, writing off your car or even in the extreme, you and/or passengers well being, then go for it.
Look at it this way, just cos you got some brand new expensive trainers, doesnt mean you can run a marathon....