I’m saying, the earlier the better. I have no problem with a 4 or 5 year old knowing that some kids have a mommy and daddy, and others have two of a single gender. They’ll know it eventually, so may as well learn. Kids are open-minded by default, so it’s unlikely that any trauma will ensue.
And it’s healthier that the kids that are gay by nature go through puberty knowing that what they’re feeling is OK, not a shameful thing to be painfully hidden.