Being someone who has some background of MMA, you should know that Martial Arts is not about being able to kick someone's ass, it's all about respect and discipline. From what you've said, it sounds more like she has a naturally dominating personality, rather than her having a lack of respect for you. Unless there are other examples you can give of things she has said or ways she's behaved that makes you feel disrespected.
At only four months into your relationship, I can see why you might feel this way because you two are still just getting to know each other as a couple. Are you wishing that she would be more submissive in the bedroom? Because if you are, then you should voice that to her. It doesn't have to be a big debacle, it can be a simple conversation where you talk to each other about your likes, dislikes, and things you want to try. Being with someone new is a great opportunity to explore your sexual desires together.
"Caring is not an advantage."