My mum sort of said something along those lines to me, she said
' you have breasts and periods, your a woman'
I replied with this
' so do you but that doesnt make you a woman you just know you are in your head. Im a boy in my head always have been'
she went quiet after that, maybe you should try it. Your friends didnt look down one day and think 'oh' they just knew, thats what i try to get people i tell to realise. Its not about privates. Suprisingly my mum doesn't know im trans lol