you are a brave , young artist. You chose a very difficult angle and perspective, brave colors, and a strong composition (the lines of the jump angling up, and the very strong pink band of color across the top).
I respect that bravery and boldness, and that you didnt' give up on this very difficult drawing. This shows you have a lot of potential as an artisti, and should save this painting so that years from now you can look back on it and see how you've grown and built on it.
Here's some advice, from one artist to another:
1. Get some watercolor paper. This will make a HUGE difference in the quality of how the paint goes on the paper. Go buy a pad. Strathmore makes some decent beginner papar that is not too expensive. Better yet is Arches, but you do not need expensive , not yet.
2. Practice shading things that are colored. An orange item will have blue as the "shadowing" color, not black. A yellow thing will have purple, a red will have green. It's the use of the opposite color on the color wheel, blended into, or lightly washed OVER the original color that creates shadows. Once you get some good watercolor paper, you can do this, you can wash one color right over a previously painted one. HOWEVER, make sure the first layer IS DRY. The paper can absorb and reabsorb, but it must be dried between layers. Use a hairdryer on low if you wish to speed up this process.
3. Think ahead of time what you want to stay white and carefully preserve it. Pencil marking will erase off a watercolor painint if they are kept light and you erase at the end, when it's VERY DRY, and use either a gum eraser or a pink pearl.
4. Be careful about the background line. That strong pink line goes right THROUGH her neck, so it kind of feels as if her head is being cut off. Even if the photo you are working from has the horizon there, you , as the artist , can put it up or down a few "inchs or feet". Make it look RIGHT, not accurate.
5. Use big and small brushes, big for big areas, small for small.
6. Do LOTS and LOTS of paintings, faster and freer, and have fun!