There are other places to practice. This is alright but if you really wanted to get better try to work more on the lineart using the airbrush, it gets cleaner lines, and just spending more time than 24 minutes is the way to get truly better. You have more than enough space to go back and make this better. And another thing, you won't get really good if you don't take suggestions for improving. It's not meant to be an insult, critique helps one learn how to improve. Take what I'm saying however you will, but if you want to improve go back to this, fix the lineart, that blue thing on her face, and look at some anatomy (or anime) books to get the body right. As I said these are suggestions, not insults.