I was exciting when each of my three children (now grown) were starting kindergarten, but I can't say I was nervous. I don't think I've ever been nervous (even about other things) to the point of feeling nauseous. (Any chance your daughter has a new baby brother or sister on the way??? :) )
Personally, I can't say whether or not it's "normal". Just because I wasn't all that nervous, it doesn't mean I'm not the one who's "not normal". LOL I can't help but wonder if you're either a very young mother, or else if you had any bad experiences with schools. It's not my business. It's just that I do think it's a little on the extreme side (even if it is normal).
My thing, right before they started school, was to try to make sure they saw school as a "nice thing" and a "nice chance to be with other little kids". I think I was so busy trying to make sure each of them was so prepared and so looking forward to school, that maybe I was more worried about how they perceived the upcoming event than anything else.
However, having said that, there are those times when we just don't remain "cool". My youngest child (and only daughter, now 26) sent me an e.mail to ask if I'll go with her to see wedding gowns Saturday. She's been engaged for months, but the picture of a gown and the reality of it hit me - and I got goose-bumps. (For goodness sake, the wedding is still a year away!).
I guess, when all is said and done, once each child comes along there will be nervousness, goose-bumps, sentimental tears, and worries like you wouldn't believe - pretty much forever.