I think the style would be fine for you (if you're worried about age appropriateness), and the length at 39" should hit just at your knee (which will be fine, too). I'm about 5'5" and I always look for dresses of this length.
I think the only concern might be that boatneck bodice if you trend toward busty. I know I prefer a scoop or v-neck just to break up the bustline a little....but maybe this isn't a concern for you.