I like the vibrancy of the first two but did you ask them to have their bras peeking out of their tops? It just looks a little trashy IMO. I also agree with the others that the catchlights are distracting. Other than that I like the first 2 a lot. The third one looks fake to me and it seems like the background is sharper than the subject.
i agree with ^^ The 3rd one looks like you just dropped in a background on it. Good looking girls but those catch lights are distracting. Did you use a ring flash and then in pp changed that catch light into a blue color?
Were you using a ring flash? I think the catchlight problem is that you minimized their pupils with the flash. It makes them look beady-eyed. Maybe a different angle would help. Third pic looks photoshopped. A good one tho.
I'm almost certain that's a ringlight. It does show really oddly in the first two. The camera is further back in 3 so it isn't as noticeable.
What I don't like about the first two is the short focal length lens. It makes their heads look disproportionately large and their noses bulbous... Not flattering on two very pretty girls. Also, in both, the texture of the wall behind them is distracting. You have a ring flash so having them stand further off the wall wouldn't have caused any distracting shadows. That plus a larger aperture would have blurred out the texture of the walls, but left the color.
About the bras... that's very common for that age group, unfortunately, and it's only in the context of us older-farts that it's "trashy".
The third is fantastic. I hope that it's not PhotoChopped and that instead you pulled this off with a rear-curtain sync, small aperture, and a long exposure!