Anybody know what this could be?

Chelsea • My name is Chelseanne. I was born and raised in north California but I’m also 42 percent British. I go to DVC and I’m majoring in psychology. I love working out, I’m trying to get into lifting and I love yoga. ❤️

My cat has had this mole looking thing on her side. It’s been there for a while and it’s pretty big. I don’t know whether it’s a mole or something more serious. It doesn’t seem like it’s bothering her but I’m still concerned.