Colors on this are fantastic and I love the choice of pose! Great job as well on the hair and clothes detail.

The only thing that seems off to me is the body ratio. The head is slightly too large and the legs might be a bit short. If she stood up and measured by her head (not counting fins) it looks as if she would be roughly 5 heads tall. Average adult is about 8 heads (about 4 from top of head to groin, then 4 more down to feet). This could work if you were going for a chibi or very young person though.

Overall great work and keep it up!