What were the principal's examples of skips being detrimental? I'm curious.
Did you read "A Nation Deceived," too? Since that's research-based, I tend to have more faith in it than in what "people" say, even when the "people" is a principal.
It doesn't mean you should skip--we didn't!--but I do think you ought to get the other side of the story before you make that choice.
Skipping can be detrimental, of course, since no educational solution has a 100% success rate and, as you note, different kids are different. But NOT skipping can be detrimental, too.
As for the meeting, I'd bring in more than you need and then be VERY selective about what you show them. If you have anything in writing (like a baby book) that can document the dates when advances occurred, it might mean more than just your word. (And yes, I know that the baby book is just your word, too, but that's how people think...)
Personally, I'd hold that early stuff in reserve and focus on the curriculum and how much of it he's mastered already, before he has even been in the class. That tends to be what schools care about. The average 1st grader can walk and write (more or less) by the time he gets to 1st grade, so I suspect that sort of detail won't sway the school as much as "He can already do everything in the 1st and second grade curriculum" will sway them!
