In an ideal, frictionless world this would probably be the correct thing to do, but I would probably focus more on simply avoiding pigeonholing a child into traditional gender roles than I would on their pronouns. It takes a while for children to learn speech (and some ND children don't). It takes a while for children to learn what sex is too aside from "you don't touch boys here, and you don't touch girls here or here."

Children ask a hell of a lot of questions though, so I assume that you'd have ample opportunities to introduce more nuance about sex and gender. In the meantime I would try to let them choose things like their toys, clothes, hairstyle, etc instead of simply showering macho toys on a kid because they have a penis, or dolls because they have a vagina. I think the most important thing is to give them agency and help them understand this stuff isn't predetermined.