Scoots on a big wheel

This is cute and I quite like the idea you put forth. I like what you did with the dust clouds. There are a few problems in execution.

The mountain she is going down doesn't make sense. It looks like it is supposed to be a dune but we see too many sides of it and it is very small compared to the size of Scootaloo and her trike.

As for Scootaloo herself the anatomy needs some work. Her legs look odd and dislocated and her hips sit very wide. While I applaud you for trying to add shadows and using gradients to create dimension they disagree on the light source. Her tail and mane are done fairly well but again the gradients are confusing and her tail shouldn't fly like that around the seat. It should either pass through the seat or bend around it. Her face isn't bad but she isn't looking where she is going at all and it feels weird.

The trike feels like it is trying to have width but the back wheel falls close to the perspective lines so it looks weird like a bicycle with one wheel slightly off. Also both pedals shouldn't be forward at the same time on one of those devices and it looks like the thing is going into her leg.

The dust is the strong point here but there are still some issues. The amount of dust she is kicking up should block out some of the rear wheels and her tail.

Keep practicing,
Inciatus