I really, really hope that no new DM reads the attitude that "If you aren't above average you're bad" to heart. Because I can't imagine how anyone would want to start DMing, would want to acknowledge that they can always improve if they're automatically labeled "bad". Nobody starts out DMing as an amazing DM. The important thing is to accept feedback, pay attention to what your players enjoy (they may or may not tell you) and don't stress out about it too much. We all make mistakes, we all have small ways in which we could improve, all of us will inevitably hit a ceiling of how proficient we are at certain skills.
I'm reminded of an analysis of a recent James Bond movie, where the analyst said that yes what Bond did was within the realm of what people can do. On the other hand there is no individual alive who could do all of those things as well as he does. I will never be as good at voices as a professional voice actor, it doesn't mean I shouldn't try. I will never have the incredible depth and detail that Matt Mercer has for Exandria, but I can still do my best to create a believable and coherent home brew world. I will never create the amazing dioramas people post on this forum now and then but that's one I'm just going to have to give a pass on, even if people do praise the minis I paint. There will always be someone better at some aspect of your DMing so don't let anyone ever tell you you're a bad DM because you aren't as good at some aspect as someone else.
Are people at the table having fun? You're doing okay because that's all that really matters.