Hello, i'm Mashkina and I'm here on behalf of because your piece was in the group's critique requested folder.
First of all, the design is beautiful. I admire that you not only thought about the clothing design, but thought her personality through, to explain why she's dressed like this. Not only she looks adorable, but her personality shows. Also, you've made it clear she's a Ladybug twin, viewer will make no mistake.
Colors and patterns match wonderfully, the cape doesn't take your attention away from overall look, yet stands out. Also, love your amount of details.
As for what needs more practice: anatomy, coloring technique.
Anatomy: her chest looks weird (looks like breasts are too high and there's virtually no waist), so do her hands (normally there are little curves on the forearms). I'd suggest you look through anatomy for artists books and try to practice drawing different parts of the body.
Coloring technique: though your colors are bright and well-balanced, it would be nice to see some gradient. Your drawing lacks shadows and highlights, and it loses volume because of that. Also, keep practicing on coloring so you get more even layers of pencil (without white streaks).
That is pretty much it. Wish you luck and inspiration