My girlfriend (19F) wants me to build more muscle (19M) and says she will broke up with me if i do not do so . What's the best course of action?

So my girlfriend and i are in a long distance relationship we are doing well but she always tell me that she do not like her boyfriend without muscle my height is 175cm my weight is 83Kg she said that she likes boys with muscle she even tell me sometime that she do not like me without muscle so in one day i ask her that muscle is more important them personality ? she said no so i ask her does she love me ? she said yes but she say that if i do not have muscle she will broke up with me she tells me that she do not like people are fat i love her very much but i am lost now