My mom hates that I'm healthy?

Hi,I'm 13.Ever since I was a little kid,I always ate junk food,drank soda.all my friends were jelous of me because their parents didn't let them eat junk.I never gained any weight for some reason.Anyways,this year I took health class and It absolutely changed me.I realized why I always got sick,why I always felt sad(junk food influences your mood),I had to eat better.When i first told my mom,she laughed and said it was a phase,I said it was a lifestyle choice.I have already been soda-free for 3 months,and I rarely have a burger here and there,other than that,I make sure I get my daily dose of protein and carbs and vitamins and everything,without eating junk like cake and sprite. My mom gets mad at me for this,she think's I have a eating disorder because I constantly turn down fatty foods,I tell her i just want to be healthy,but her being a phsycologist,she thinks she know me so well and that I think I'm overweght.I dont! She still eats unhealthy and she gets mad at me when I grocery shop with her and ask for yogurt instead of pudding,or whole wheat instead of white bread.I can never convince her,she thinks she knows everything and everyone,and I told her "would you rather have me obese?" and she just called me anorexic because I wanted a veggies style burger at IN-N-Out(lettuce instead of bun).I dont know why being healthy is so wrong?