It's not that I'm actively educating my daughters about LGBTQ+ yet but they are at the age of learning about relationships and any time we or they talk about "when I'll have a boyfriend..." we will comment "...or girlfriend whatever you'll like..." I mean I at least try to keep them open minded while not forcing it, at least if and when the time comes they'll feel comfortable to tell us.
I understand your intent, but I reckon kids know really early on. My daughter has been boy crazy since 5, so I never bothered with "or a girlfriend" type comments. But we do instill in her regularly that love is love and partners come in all types.
As a late 20s asexual gay person, I was in complete denial until my early 20s about my asexuality and until my mid 20s about being gay. Not because my parents weren't accepting, but because society is heteronormative. Always good to reinforce an open, positive attitude!