its a good portrait. even if it doesn't follow the rule of thirds
but theres something about the positioning, it just doensn't seem right. theres jsut somethign about it i can't put my finger on.
maybe theres too much dead space on the bottom right, and the fact that the hat is cut off but not the chin
just a side note: i've read, that for women and children, the subject should tilt their heads towards the forward shoulder, a lesser extent on children. this is to create a sense of softness, feminility. and with men, they should slightly, tilt thier heads to their back most shoulder to give a sense of strongness and masculinity
i think it should have been shot vertical to make her head not look so square, and phototrons edit looks harsh to me, but im not on my monitor so i can't be sure.
this may be a daughter or whatever of yours, and so for you the expression may be priceless, but for us outsiders its only a strange smile.
i would have moved to the right some, its strange looking to see both corners of the mouth but still not feel like i can see the lips all the way across (on the right side before the corner of the mouth they kind of disappear. also its kind of ackward to fully see the whites of the eyes, like on both sides of the colored parts.
I think this shot is lovely. Yes it is a little dark, but that is easily fixed in post processing. Was this a candid snap or were you actually doing a session? I think you captured a very cute expression and I don't see anything wrong with the cropping. If this is your first portrait this is a great start!