R.J.
Big hugs mama. I personally didn't sleep at all the night before kiddo started preschool (in fact, I had to go take a nap after dropping him off and I kept the phone in my ear the whole time)... and had a repeat with K.
K was *terrifying* for me. I had visited over 50 preschools to find the "right" one... but had no choice at all in elementary schools. Well, sort of. Because we were in an apartment the district chose to assign our son to be bussed to a school over an hour away (discrimination, much?), so we used our childcare address instead and hopped districts. But still. 2 vs 50. I lost sleep all summer, and didn't sleep at all the night before.
Of course, he was fine. I was just a wreck.
I REALLY have to 2nd the fact that there is no such thing as a perfect placement. The school itself that kiddo went to was awful (not dangerous, or badly funded, the school board just decided to jump on the bandwagon with really crappy curricula/scope&sequence... the other school he would have been bussed to was actually dangerous), but his teacher was amazing Amaaaaaazing. I still want to go give her hugs whenever I think of her. Now we homeschool (for many reasons) and not even THAT is perfect, and I get to tailor everything to him & his needs & his learning style & his interests. Sigh.
IMHO 1/2 of life is learning how to overcome obstacles. You won't know until he starts school what those obstacles are going to be. Great school, lousy teacher? Great teacher, mediocre school? Social problems? Academic problems? You just won't know.
So there's nothing to do but throw the baby in the river and see if they can swim. Then you're dealing with the real situation, instead of "maybes" and you can actually make reasoned decisions based on experience. AND you'll learn a lot. So you'll be able for the *following* year (aka by xmas break) to really know what you want and what to look for in a school.
Hugs again. ((Sometimes I think all Kindergarten Mums should be having a sleepover in the gym... none of us actually get any sleep... and that way we could at least be setting up playdates). But I guess we should count our blessings. Next thing ya know our babies are getting their learner's permits!