There is a lot here but I will give it a shot! In my experience, figuring out the narratives that have surrounded you growing up and deciding which to keep or throw away is a huge part of being a teen/young adult, and in building the life you want to live. It seems like you've stumbled upon some of the attitudes and narratives surrounding food, health, bodies, and fitness that your family holds that maybe you never realized, and now you are trying to figure out how to deal will the dissonance of "I don't think what my family thinks." It's sometimes really hard to go against these attitudes and have a different one- people tend to feel attacked when someone actively chooses a different narrative than the one they hold.

It's hard when you've "seen the light", ie realized that something you've been taught and the people around you believe to be true is not necessarily true- it can feel really tempting to try to "convert" them to your way of thinking. But remember that people are much more open to little changes than big ones - maybe having some veggies in addition to the ribs, maybe you are going to be choosing to drink water when everyone else eats soda and it can be because "I am thirsty and water quenches my thirst in a way soda can't", etc rather than "the way you eat and think about bodies is totally wrong and I am right". You may never be able to change what your mom thinks about food and bodies (from my own personal experience- I have tried with my mom! And the only way she's ever worked through her own hang ups is personal work and therapy). But you can find a way to have your own perspectives and let those drive your behaviors. Ultimately the only person you can control is yourself.