You are being unrealistic if you think a computer game will help you drive a car, lorry or white van to give you any useful experience, you cant press ctr, alt,delete and unkill yourself.
have you got a full car licence, any driving experience or road knowledge? map, nav system etc
have a look at a young driver scheme, visit a local haulier, talk the talk and get them to pay for it.
£2.5k is about the norm for your first test.
But age is no bar, apart from maybe an excessive insurance
premium