I really like your composition here. There a some good lead-ins and your exposure seems good (maybe just a smidgen on the dark side). It's a pity that one of the girls face is obstructed by the other's arm though. (7)
Nice contrast of colors which I think works well here due to the cloudy/muggy Chicago skyline. One question though, why does everything appear to have sharp focus (people, benches, leaves, fence, boat, buildings) EXCEPT the flowers? I wonder what the shot would look like with a shallow DOF with the flowers in focus and everything else slightly blurred but not too much.