Nice pics.Yes that is where pre-flowers(pistils) will show.Looks a little early,as that is new growth showing.Patience my friend.Have you switched to a 12/12 light cycle?
it may be early to tell and i still wouldnt pull it until 100%, but i would be leaning towards that being a male. looks like a small stem at the base of where you have circled.
edit: also you should trim the 2 single leaves at the bottom and add more soil. i use a growing mix like promix and dont add anything, so as far as adding anything to your soil idk.