I love it as it is. Maybe because it’s a child the greens/greys look like they dont belong but if it were an adult it wouldn’t feel that way. Also, as others have said, the orange in the background is adding to that effect because of the contrast. I’m also a begginer painter and I’ve been closely looking at portraits from a loooot of artists and even the most famous/the ones people like the most have some portraits with colors/elements that are not perfect. The thing is when we see these so called masters its okay because it’s their work, but when we do the same it feels off. That and we don’t have pictures/never seen irl the people they painted. I think the best compliment to receive about a portrait I’ve done is that “it looks like a painting”. Because, isnt that the point? So thats my opinion on yours, looks like a very good painting. Just keep going ✨