Starting from scratch is very good, but it takes some skill. Considering that this is your first sprite and you don't consider yourself an artist, it's not bad, but you need a lot of practice. Using a base or other art, although not good for final pieces, is a good way to learn.
I used the images Fushigisaur showed to make a proper base for you. http://i.imgur.com/ZYnobYy.png You can use this to practice basic shading of clothing and hair. Don't only use this base though, it takes longer but using a larger base (say, 40x40 or 70x70) can give great practice on the details as Fushigisaur has already mentioned.
Although you don't have to know what you are planning to make your art for, if you do, you'll have a goal. Goals are the momentum to keep you going when your art is junk (which it will be sometimes), when you are too lazy to put in the time that this can take (which you will be sometime or another), and it usually means you will end with something nice.
Happily for you, this was my first sprite. Your first sprite is much better than mine was, and I have come a long way from that, so you too can undoubtedly get better. I made this years ago, when I was quite young, so it will still take quite some work for you to get good.
And if you need any specific help, you can PM me. I'm not sure if I'm willing to tutor you thoroughly, but I can give you advice or a tip whenever you need one, and I could link you to some very good tutorials.
Edit: When you make more, post them here. I'd love to see them.