Hi Elisabeth! Welcome to the forums
You have a really nice style, very cute and modern and relevant to today's industry, I think! It looks like you have a strong foundation of anatomy and perspective as well! I think you're at a point where you can start focusing less on how well you can draw things, and more about what you draw. Meaning, you can start focusing on storytelling, composition, lighting and colors to best express what you're trying to express.
In this illustration for instance, it is very busy and there is no clear focal point. The eye kind of wanders in and out of the picture without a clear path that you decided. I'd suggest to decide what is the focal point of your picture (for instance, it could be the girl in the middle who is counting) and tweak the lighting, values and colors around that area to really put more contrast and emphasis there and make her pop. Then, reduce contrasts and popping colors in other areas of the illustration that are less important so that they don't steal the spotlight. For instance, that white stuffed toy on the bed, the stars out the window and the colorful triangles hanging from the ceiling are really eye-catching, but I'm not sure they should be! This really is a very busy image, don't be afraid to have places in your image that have less detail and that can counter-balance the areas that do have a lot of detail. Maybe put a bit more shadows on the hidden kids to blend them in a little bit more? These are some of the little things you can do to tell your story more clearly and effectively But as I said, this is a very beautiful and attractive illustration altogether and I think you're really on to something! I wish you good continuation on your journey