It's too short, honestly. It's short even for a children's novel. As for novellas, it's EXTREMELY unusual for a first-time writer to be accepted on the strength of a novella. Not many places will publish a novella anyway.
Develop it. You need to be looking at over 100,000 words for that kind of book.
Or write another, of course

My first three novels are languishing in a drawer. My fourth is being published. I tried to lengthen an earlier novel but simply tied myself in knots. It was easier to write a completely new one!