I put this in the comments but feel might aswell repeat it properly for it bares repeating and expanding.
As an ace & sapphic/lez, I knew all of it 6. Hilariously recently I learned I'm also intersex and sure as heck makes some other things click.
Basically starting at 4 to 5 we are surrounded by adults getting all teasy about cis relationships things and all the playground games that surround such too. Also to various degrees TV shows, movies, books ans such also hit you over the head with cishet and romantic relationships in general.
I find it fking hilarious that cishets go pearl clutch panic when it comes to us expressing our experiences and any media that reflects such.
Yes that is hella young but the literal world pushes cishet as default, the vast majority of media we consume at that age, re the adults that tease about relationships when simply making friends of opposite genders. There is no fking way to escape it. I tried lmao.
Do you even fathom how broken and wrong I felt at that age with nothing reflecting what I felt, what I was experiencing? This was the early 1990s.
Add ontop how cruel other kids that age can be for any difference. I'm autistic with adhd,c dyslexia, type 1 diabetes and some ocd tendencies.
My elementary years were a living hell from grade 3 till grade 7 when we finally moved. Daily bulling, teachers basically condoning it by doing fking nothing at all and blaming it on me every single time. One even said to my face "Why did they keep a broken burden like you."
To this day I still trip hard on feeling like I'm a burden, a waist of air & resources, even with thousands of hours of therpy over the years.
Fk the hell soooo off with "their a child how could they know."
WE ALL KNEW. There was, in some ways, no way not to learn and figure it out when you don't feel the same or feel drastically different on such topics from others around you while it's being teased and talked about by so many around us.
The reason media for children is so deeply deeply important is so they don't have to feel alone and broken and hurt in ways that would scar them like it did so many of us.
I'm gonna go have a cry now.. do fking better.