How to convince my mom to buy a scale?

I really wont to by myself some weighing scales, Just to check my weight nothing more im not obsessed at all. We was in a shop and there was some scales I asked my mum for some and she said no You cant have them I dont wont you obsesing over your weight....

Im not allowed to have none. How can I convince my mum that I wont be obsessing about my weight I just wont to check every month how much I weigh?

Just visit a store with scales once a month or go over to a friends...Good luck !!

scales are quite cheap so why don't you buy them with your own money and hide them in your room?