Don't be devastated. You'd be surprised at the number of kids who receive speech or OT early on. It's just a little push to help them catch up to their peers before the more difficult curriculum years of school begin.
My oldest daughter was diagnosed with Autism late after several evals which were fairly useless (despite her having almost no language and other severe problems). My middle one, who seemed perfectly fine compared to the older, was hit in Kindergarten with such a harsh eval that she sounded (from the write-ups) like she should be a speechless, low-IQ cripple. This was a huge surprise for us, considering her comparison to her older sister. The staff at her school however were all wonderful, and after one year of PT, two years of OT, and three of speech, she is leaving her IEP days behind and is totally caught up with everyone else (and ahead in a great many areas).
So I would say: don't worry. In our district, my daughter was in the regular classroom and pulled out (with one or two other children, usually) for small periods of time during the week to go to therapy; the therapists also came to the room to work with all the children once a week. She loved going to therapy (was great fun to her -- was sad when she couldn't go anymore!) and she loves school in general, even when she has trouble with some concepts (rare these days). She was always a happy child and has remained so throughout her therapies -- several teachers have commented on this!
She is now either completely caught up with her peers or ahead in all areas. Maybe she was just developing at her own pace, but I am glad that she had the opportunity to be helped along in catching up while the curriculum was still easy to understand and the other kids too young to really notice or care.
You should definitely contact your school district about integrated preschool. If she qualifies (which it sounds like she will), then she can go there, and both the preschool and in-school therapy costs will be covered by the school district (a bonus!). Then she will not only have the opportunity to catch up, but will also be familiar with other kids going into kindergarten, and maybe the school itself (if they have an onsite integrated preschool at the elementary school in your district -- they do in ours).
I wish my daughter had been diagnosed in time to do this; she would have caught up much sooner (in kindergarten she was very shy and quiet and had trouble making friends). The irony in our case was that we couldn't afford preschool, where her problems likely would have been noticed sooner. Which would have allowed her to go to the integrated preschool for free. Yeesh.
Good luck! Don't be worried; your daughter is still the same, no "label" will change her, and she will likely grow out of the need for help before you know it. The school should have no vested interest in keeping her in the sped system so don't worry about labeling (and at least in my daughter's case, none of the other kids ever treated her differently). If anything, the school will want to make sure she catches up in time to take the MCAS in third grade so their scores aren't hurt. :)