We have multiple identities. Whether we want to admit this or not. We do not and can not control them all.
Our identity as self is just one of these.
We have multiple other identities which are social and relational. Eg a parent child relationship and identity. Or our collective identity as a woman. You can not escape this. Other people can say you don't fit the criteria of this identity if they wish; you don't dictate terms of identity. Other people have a say in shared identity formation and sustainability. You don't get to come along after thousands of years and rewrite the rule book because you say so, against the explicit consent of others.
Whether there is conflict between your self identity and relational identity you will not resolve matters until you resolve this conflict - or to put it another way, you can never escape who you are and where you came from. It is central to your identity and how it's formed. Normally such statements are about class and race but it's as applicable to gender identity.
You can pretend differently all you like, but it will only ever be superficial. Deep down you know this.
You can put on a performance and go into denial. But there will almost always be someone who knows who you are when this mask comes off. And yes it's usually family who suffer with this because if someone spends all day putting on a performance, and then unmask at home they usually unload that build up of stress onto the people who can't judge because of blood ties and instead are bound by obligation.
You can't suddenly say I'm the eldest daughter of my parents and change their identity as parents of a boy and a girl (and how they relate to others from this) not can you displace the only daughter to being the second daughter. That wasn't your lived experience. It wasn't their lived experience. Every relational social interaction growing up was about a brother and a sister not two sisters. It wasn't two sisters arguing over clothes or boyfriends. It wasn't two sisters with hormones going off left right and centre. It wasn't mum talking to others about how her two daughters got on and how her husband would really liked a son but he was amazing with both daughters and wouldn't change it for the world.
Because this is a fiction for everyone concerned.
The reality is dealing with the transition. It's dealing with the unfair shittiness if you make a mistake even if you have tried hard. The reality is requiring everyone else to play best supporting actor or actress to uphold your singular identity.
And not everyone is good at acting. If you are putting on a shit 'performance of feminity', they can't polish a turd even if their own performance is Oscar winning. You are still a shit actor regardless of how you identify.
Everyone will see through it.