My plan currently is to apply when 25, when have finished my masters degree and have done a year of work so have some money saved up. Though may apply when 26 if money is an issue, after a further year of work. I wouldn't see these as wasted, as could probably take part in research and stuff as well as getting new caring and voluntary experience etc., as well as reading bulky textbooks (Bought Davidson's principles of medicine, crazy big but seems useful).
Thinking of going for GP if I can, as I'm more of a generalist than a specialist sort of person. I get bored easily ^^. It's also quite a bit shorter, their training, than to be a consultant.