Am I just trapped

a bit ago my mother randomly came up to me saying how glad she was that im "not one of those boys who thinks hes a girl" and how well she raised me, i laughed it off but it felt like she was spitting in my face.

its impossible she knows and id never tell her, shes not the accepting type so though i know its not something i should want is it at all hidable like can you transition physically while hiding it at certain times,

im also old enough to where she cant see any of my medical stuff

The only reason I'd wanna hide it would be not wanting to cut her off as even though she wouldn't accept me I feel id be hugely unfair to cut her off ,