My DS is a late everything, walker, talker, self-feeder, good sleeper, all of it (NCT groups were fun!). When he gets to the main milestones, he does it easily and happily. When he walked he just did it, never really fell over, never had to worry about him crashing to the ground. Once he was talking he had a HUGE vocab straight away and could chat away easily. I'm hoping the same is true of potty training as he's 2.7 - if true to form he'll suddenly decide to ditch nappies and be dry at night immediately.
Just trying to emphasise the positive. EVERYONE I KNOW has children who have passed the major milestones before my DS, which was really difficult when he was tiny and I had PND, not I see that he's a bright, wonderful 2.7yo. Yes, he's the last to potty train, but I don't give a shit anymore.
One thing he's always been ahead of his peers is empathy - he's such a thoughtful, kind, generous, funny, loving little boy)
Sorry, this has turned into a 'my boy is best because' post,
also:
My DP doesn't remember anything before he was 6. He was a very late talker (3.5+) and he's exceptionally intelligent.