I agree with cym and squirt. My DS has the same summer birthday issue and was accelerated from 2nd to 3rd in mid-year. He spent the second half of a year in third as a seven year old when most of the boys were 9 turning 10. He was much happier socially with the older kids, and was teased less than when he was in second.
He is also a very asynchronous kid who can seem very immature one minute and very advanced the next. He is also a rather wiggly little thing, with tons of excess energy. All of these things considered, third grade was a much better fit for him.
I wanted to pass along two points:
1) The public school decided DS needed a grade acceleration based on his second grade teacher's assessment. Without any prompting, she gave DS the end of the year tests in all subjects by October of his second year. She also talked to the gifted teacher about DS before recommending a grade acceleration to us. You should be able to ask for the same thing. If the school is dragging its heels, you should be able to say, "Look, in the week before school starts, give him the end of the year tests." If he passes them, then there is nothing left for him to learn in that grade. You can also ask that they do out-of-level tests to find out where he is, but those take a long time to order, administer, and grade.
2) Most schools follow the Iowa Acceleration Scale (IAS) for determining if a child should be accelerated. It is a very detailed process that evaluates the child's intellectual needs and emotional needs. My PS (public school) formed an acceleration team that had my DS's current teacher (2nd), his previous year's teacher, the gifted teacher, the principle, and the school psychologist. They gave him the WISC-IV IQ test, and somehow tried to evaluate his out-of-level knowledge. (we are trying to find out if they gave him any achievement tests). And the school psychologist talked with him and tried to assess his emotional and social maturity. All of these voices had to agree that acceleration was a good option for this particular kid at this particular time. I'm glad the school was so cautious, but it took 3 months to jump through all of the hoops to make it happen. Also, part of the IAS is asking the kid what he or she wants. If the child says at any point that they do not wish to be accelerated, then the process comes to a complete stop.
As a parent who spent three months agonizing over whether to accelerate or not, I understand your concerns. Eventually, you just have to go with your gut feelings. You know your kid better than anyone else. Just try to listen to what you think is best for your child. (and yes, I spent three months of not sleeping well due to worrying, so I know how hard it can be.) I had it easier, since the school was recommending the acceleration to me. You might need to fight for it.
Hope this helps!
Oh, and one more thing. My school didn't play the "summer birthday" card. They played the "product" card. When you move up in grades, more of what the child knows is measured by producing a "product"... like a book report or science report. The one concern that the teachers had with my DS is that he did not write very much daily in his journal, and his left-handed scrawl was a bit slow to produce. Sure enough, within a month of moving up to third, DS had to do a science report. It ended up being 19 half-pages long, which was quite taxing for him. Science is what he lives for, his joy in life. But getting all of those facts that were swirling around in his head down on paper was a challenge.
