It's pretty good for being your first digital work, and without a tablet to boot.
I assume you used Paint for Windows 7? It does look like that, so I wont nag you about layers. But honestly, I think Paint is still more suited to pixel art.
You forgot the top of her head.
The shirt should go under the hair. As in coloring the shirt first, then the hair. Or fix the hair after coloring the shirt, that works too.
Maybe you should shade under the bangs?
Her head is kinda wide on one side.
The eye are kinda blocky, especially the pupils, so I'd suggest that you'd zoom in when drawing digitally, because it does look like you didn't. Zooming in tends to help a lot when drawing details and detailed things, such as eyes. I mean it.
And there is a rather large gap between the mouth and nose.
I hope you didn't find this too harsh. You did a good effort on it, I'll give you credit for that.