Enjoy the experience and roleplay what a newborn/toddler/child would actually do at your character's age, like crying because of hunger, babbling, slowly learning to crawl and walk and speak, getting to know the world around them while being taught things they need to know by their family, like how to make your own food and everything you should know about the race's unique culture. Some races might even have unique vocabulary for some things.
This is one of the things I am really not looking forward to. It sounds like it's a pretty ridiculous thing to be required to do. RP your character as a newborn baby? I have kids. I know what newborn babies do: Sleep. When they're not sleeping they're eating. Or crying. Or pooping. (If you're lucky they're pooping. If not... Well, that's a whole 'nother problem!)
How fast do characters age? Because personally, I'd just love to fast-forward to the part where I can at least walk, talk, and do stuff.
