That is awesome beyond words. (Good name, my son is named William also )
1. Get sleep now.
2. Enjoy the period now, for about 8 months, where if you put them down, they don't move on their own.
3. Ages 1-12 are magical, enjoy every minute of it.
4. But try and ignore the Age 13-17 years; you can't kill them, and you can't put them back.
Congrats again!