What weight do you have to be to get your period?

I was asking my mum when I was going to get my period, but she said you have to be a certain weight but we dont know the weight. I want to know when I will get mine, I know I'm only 11, but I've been getting discharge for three years, I'm 30A, I have lots of pubic hair, BO, spots, wide hips and I'm five foot, I don't know how much I weigh though (mum doesnt approve of scales)