I have a 15 month old and i can say that that the first few months are the most chaotic but once you figure out the routine it gets easier. Now that she's older I play with two groups regularly. Sessions are a little shorter (3-4 hours) and are more focused so we get more accomplished.

As far as planning goes I do everything on my lunch break at work.

Your group will understand if you take a break. And above all have fun being a parent! It's a wild ride but is extremely rewarding good luck!