Very nice work!
Yeah, the lips are probably too big, but the breasts are fine. They are normal sized, and I'm pretty sure with that type of swimsuit, it probably doesn't really emphasize the "roundness" - it's more of a sportier suit. (Not that I have any experience trying on women's tops or anything, mind you.

) Maybe it's the fact that the women is facing the viewer head-on that's causing the issue here... normally if a woman is at more of an angle to the viewer, you'll see more of her "curves."
The thing that really stands out to me is the lens flare... I really think it's unnecessary, and just detracts from the rest of the image.
Oh yeah, and some of the highlights from the sun on her skin seem a little out of place, but maybe that's me.