I know the histogram doesn't necessarily tell the whole story but it looks about right - there is a little peak right at the right-hand side but that will be the sun flash near the nose.
I'd therefore welcome a second opinion, especially as this was screened by a screener-in-training.
I've always argued this site harshly, and in my opinion wrongly rejects some for being overexposed. For me, your photo is properly exposed and is in no way overexposed. There are many other recently accepted photos that I was surprised were accepted for being much brighter than yours. In my opinion, your photo is nicely exposed and is bright, but not overexposed.
Equipment: 2x Canon EOS 50D; Sigma 10-20 EX DC HSM, 50-500 EX APO DG, Canon 24-105 f/4 L, Speedlite 430EX