its not too much flash, its that you have it on camera I think. if you had it a bit off camera the look would be a bit more dramatic...its all preference though. this isnt bad.
I think the biggest challenge here is that you have wonderful warm light in the sky and cooler daylight balanced light (flash?) illuminating your subjects. I think a gel to warm the light from the left of the frame would have helped.
Composition: would have positioned the 2 girls a little off-center maybe to the right.
Lighting: doesn't seem even. I could be wrong but the flash on the figures look a bit too artificial (see the harsh shadows) compared to the nice natural light of the sky.