Hi,
To start I wanna say I'm writing this post in good faith to provide the viewpoint of a Trans person with Gender Critical parents but I know this is the internet and this will probably just be trolled to death but here goes.
I had a pretty regular 'happy' family setup, and apparently first told my parents of my identity at just 5yrs old but the first I remember is at 8yrs old when I refused to go by my 'very gendered' birth name but my parents insisted on using it especially publicly.
My parents were never particularly strict on gender roles in the home - my sister would wear my dad's glasses and jacket and stomp around with his briefcase in hand and my brother had an emo phase with heels and mascara to match and apart from some grumbling from my father it was never the biggest issue in our house.
Sexuality was different though even though my father would class himself as a pragmatic centrist, barring a socialist university phase, and my mother a card-carrying progressive New Labour type whose Best Friend was the most flamboyant gay man and an Aunt who lived with her 'friend' until she passed. There was an uncomfortableness with sexuality where both my parents would call it a lifestyle choice and opposed gay marriage - cut to three years ago when my older brother came out as bisexual and last month the youngest sister as a lesbian 
but rest assured the other 3 siblings remain firmly 'normal.'
Back to me and by 12 I had started puberty and was experiencing debilitating gender dysphoria - I would look into the mirror and see nothing that matched my brain. I would continue to feel this way until the bullying and dysphoria got so bad that one night I climbed into my bathtub with a kitchen knife hoping I could change my body to fit my brain somehow I managed not to perform self-surgery in my bathtub.
A couple of months later I came clean to my parents, I wasn't expecting a big hug but I wasn't expecting what came next. They ignored it as if I had told them what I wanted for dinner, they decided they didn't hear what I had said at all.
Over the next year, the internet became my friend as I found ways to affirm my gender by doing hidden things at first and then slowly more outward things. I came out to my siblings and although they found it confusing my oldest brother and sister were a godsend who I wouldn't have survived without, They helped me pick out a new haircut and new clothes and we came up with a new name.
I came out in school and sure there was bullying but I was feeling so Euphoric that it almost didn't matter. When the teachers found out they informed my parents and that's when everything changed! My parents sat me down and said I was just confused. They threw out my new clothes, anything that I used to affirm my gender, even my shoes and magazines then they took my bedroom door off and took away my laptop and phone and forced my older siblings to refer to me by my birth name, my older brother and sister stopped supporting me and I lost my only family support and anything that was helping me.
Eventually, when they realised everything they had done hadn't worked and I still felt the same way, they decided to try both religious and non-religious conversion therapy which left permanent scarring to my mental health and I frequently have nightmares about it.
At 15 I had my first suicide attempt and my parents forced me to lie and say it was due just to bullying at school but that wasn't true it was the dysphoria and conversion therapy that was killing me.
From 15 to 17 I had multiple suicide attempts and after the third one, my parents finally allowed me to stop the conversion therapy but still forcibly live as my 'biological' sex.
Eventually, I managed to get to a great University and at 18 I socially transitioned and by 20 I had started hormones. I now have a job that provides me financial stability and have an amazing partner, with 2 children from a prior relationship that I now consider like my own. We are also now having a baby very soon.
My mother now describes herself as Gender Critical and frequently posts online about how she will be unable to see her grandchildren because of her views, which is true as I will not allow my parents to see either my child or stepchildren.
My parents continue to refuse to acknowledge my identity and pronouns. The last time we talked, she said she believes I am just gay, which neither makes sense considering my partner's gender nor the fact she also has a terrible relationship with my lesbian sister and bisexual brother who also rarely allows his child to visit my mum, due to her comments about their sexualities.
I finally have the support back of all my siblings and we do frequently gather without my parents. I hope one day my parents change their minds but honestly I don't hold much hope and I don't know if I could forgive what they did to me.
A lot of online trans activists wish trans children for Gender Criticals but I don't, it wasn't very nice at all. If you're going to ask if I think kids should transition, the answer is I don't know as I didn't transition as a child and a social transition helped plenty for me.
Well that's it I think, just the perspective and experience of a trans person with Gender Critical parents, feel free to ask any reasonable questions or respectful questions. 