I think it’s honestly just an age and lack of experience going here. I’d suggest getting into your local community. Finding a mentor. Attend some munches. Learn about the lifestyle.
At 20yrs old you’ve been able to legally explore kink at best 2 years. Most clubs and dungeons actually limit to 21 and up. If we’re talking strictly biology here. Males don’t reach full maturity mentally/emotionally until mid 20s at a minimum. So on that biology fact. You are not yet developed enough mentally emotionally to take on a submissive and care for them and keep their best interests at focus, when you yourself are not fully developed.
Ironically old guard, high protocol, and the leather communities of bdsm. They started all people off in a submissive role to learn the craft and then advance into a dominant role after gaining the experience. I’m not saying this is the only way. I myself never subbed. I had a Dom mentor locally. But consider there is other ways.
If you’re going to enter the lifestyle with the narrow mindset of male =dom and sub=female, you’re going to set yourself up to be passed over as legit Dom.