I think modelling isn't degrading in a physical sense, physically you are rather exalted, you are up on a stage above the onlookers, you are decorated with make up and clothes. You are there with the expectation that everyone wants to imitate you.
I can understand your mother's concern that people will only value you for what you look like or represent rather than who you are and what you can contribute in a more tangible sense.
It is a bit degrading to parade yourself before others, you are at the mercy of their opinion.
But I think it's worth trying in your life but I don't think it'd be worthwhile to do as a career. I would never let my child do it or be in a beauty pageant for this reason. Good for a bit of ego and fun. I think it'd be damaging to your self-esteem and development in the long run.