Great to hear you are adding to your 100 kids quota and it's a great start. I like the idea of mixing patterned textures onto the character and I think your could probably take it further by using on other areas of the clothing or background which will help it blend in more. I would also suggest exploring a few different color schemes as this one is quite an unusual choice as the leggings are the most eyecatching with such bright value and saturation, especially in contrast to the grey background.
I like how you have drawn her face, but i'm curious about what she is doing judging from her pose, it almost seems like the "i'm a little teapot" pose which I thought "topo" referred to at first until I saw what you wrote about it.
You mentioned that you were "slow" in illustrating the kids. Which part is slowing you down the most? I would be interested in seeing your process to try and speed it up, or at least be more efficient if that is what you are looking to do.