When did you first hear about genders other than male/female?

I learned about it in 2011 at high school during a week in 9th grade where we went to specialized one-off classes like Sex Ed. One them was about gender diversity and I remember them talking about how people can just have no gender and/or have their gender be themselves. Like "Dave's gender can just be Dave, they don't have to be a gender or can have their gender be unique to them".

Now it's 14 years later, almost half my lifetime has gone by and people are still uneducated on gender diversity??? I'm wondering how much I'm in the minority on learning about gender diversity around 2011.