Okay, so I will try to make this short (otherwise I might get so mad at society that I'll have a mental breakdown).
At some point in your life someone will make fun of you and your physique.
"You're underweight? Eww eat something, you need a bigger ass and bigger boobs."
"You're overweight? Eat less! No self-respecting woman should have a muffin top or have to wear plus size clothing."
Your beauty isn't defined by your weight.
No matter what you look like, people will always hate on you, the important part is to love yourself, you are the only one that is allowed to criticize your body, but you shouldn't start hating yourself just because somebody else thinks everyone has to look the same. You don't have to be a size zero to be stunning, there is no such thing as a "perfect body", we all have "flaws" (which are only flaws because society makes you think so), embrace your "flaws" and be the best person you can be.
At the end of the day, your looks count for nothing. If you're a rude fucking bitch, nobody will fucking like you (in most cases, Donald Trump has supporters even if he is an asshole, but idk why). So yeah, just be a good person, stay positive and don't make fun of others for things they can't (or don't want to) change.