I made an edit as a warm-up before getting back to my pixels.
You've got enough pixels to add some shape and form to the figure. I went with softer, rounder shapes to make it more feminine.
Added mass to the hips, and raised the hips one pixel up. The groin is about halfway up a normal figure, and for a jump and run character I think it's good to keep the legs long.
Softened the shoulders a bit, narrowed the upper torso to make it more feminine.
I didn't get the front leg correct, You could probably pull the whole thigh down a pixel and it would fit better. I am still rather poor at hair, so ignore those bits.
Some thoughts:
Teenagers are usually not fully grown. Which means less than 8 heads high. Or a larger head on the same body. You could increase the size of the head a pixel or two and it would be fine. This would give you room to add a mouth if you wanted one.
The lightest green is a bit bright. Be sure to take a look at it on the real backgrounds to make sure it looks ok.
Hope this helps,
Tourist