Well, she is not overweight. My DD weighed more than that when she was 7. She still had baby fat up until around the age of 10. Then she really stretched and thinned out. She's almost 14 now and is a beautiful figure skater with lots of lean muscle. The belly went away when she got her growth spurt at puberty.
If the blood work doesn't show problems, try not to get worked up by it, especially around her because the last thing you want her to have when she's a teen is an eating disorder by thinking she's fat. Not saying you are doing that by any means. She's right in the middle which is perfect.
I agree about the eating disorder! I hope she never knows I'm concerned! Right now we talk about food as being healthy and not healthy. We've made the changes for the whole family so we're all benefiting from it. You're right, though, it's very possible she'll outgrow this or that this is all just normal for her. I just want to cover my bases so someday I'm not saying "I wish I had known earlier". I think that's my biggest fear.