I do follow illustrators and am an avid art fan. I just wanted you to answer my question and provide proof that Amanda Oleander is the first person to draw like this.

I've seen this style elsewhere. The colors, bodies, faces. It was fairly popular in the 90s. Who is to say Amanda isn't copying someone else? Do you have a concrete source that states this is her style and her style only?

I don't see the point in crediting Amanda if she didn't draw it. I looked at OP's other works and I can spot some differences, enough to see that they're just inspired. I'm not in the illustration world but I've read a lot of children's books and this style isn't that unique, all things considered. Amanda just happens to have a large following. And we have no idea if OP was drawing like this before discovering Amanda or before Amanda gained popularity.

Amanda Oleander didn't invent this style.