P.H.
I am going to say something that others may find to be totally off, but I almost think it is easier for boys to have this condition because to some degree they already have more impulsivity. My son has ADD, I always suspected that his "little boy behavior" was actually something more than that, but just dealt with it at home with behavioral controls. I'd only had experience with girls prior to his birth, and so didn't know for sure what to expect, only that it was TOTALLY different from his sisters behaviors.
But at around age 9 we actually had to get a diagnosis for his continued success in school. Things are harder for him in many ways, yet he perseveres and is making A's and B's. He's mostly got friends who are boys, and a few girls.
Socially, things are just different for boys.
I think that your daughter has friends. The boys she hangs out with at lunch qualify, she's young yet. Maybe girls and all the weird cliques and social intricacies are just boring to her. Boys are much more straightforward about stuff, and often do more interesting things.(Tomboy behaviors can be outgrown eventually, I used to be one and I hated playing with girls.)
So she doesn't play with dolls, or jacks, or want to wear dresses....she still is learning social skills when she is hanging out with the boys.
I made friends with other girls through sports. Maybe see if she likes to play any. By the time I was in Middle School, I still hated the stupid social strata that girls had, but I had some friends who were girls.
My mother wished I wanted to play dolls, and wear pretty dresses like her friends' daughters. I'd rather be climbing trees, and looking for frogs in the ditches. Give her some room to grow.