it takes as long as it takes... some people take to it better than others
though some instructor are on the make...my first load of lessons, i realised he was doing the pedals for me discretely so when i drove another car i was a a bit 'off'... he then cancelled 2 tests on the day... turned up for one in a totally different car that i was unfamiliar with ... and i realised he was just an old perve who wnated me to keep having lessons...
also they are much stricter nowadays and will be looking for every little mistake, expecially at her age...
i was told this by an examiner who i think felt a bit bad for failing me a touch unfairly...but he said he could tell i wasnt ready.
he said they see so many drivers who really shouldnt be on the road, but just because they managed to drive for 35mins without doing anyhting wrong they passed... so they look for any little thing to add, if they can 'just tell' that they have 'fluked' it...
the best thing to do is go for more private lessons... start with an instructor to go over the basics, and then its more about confidence and gaining your 'sea legs' if you get me...just getting used to the road...
i found i drove much better in my own car than an instructor, i think because i alwasy felt he was in charge and i was just following orders...when you have to think for yourself and you are totally under your own control, natural instinct kick in more and i gained confidence much quicker