Unfortunately I didn't start biking a lot until my daughter was a preteen. And I don't know a lot of parents who bike with babies. I wish I could offer more advice. My understanding is it can be done safely and conveniently, and that you have to be flexible, as with everything with babies. Whether you wait a year until the baby is old enough for the bike seat, or get a trailer, I think it would be a lot of fun. The other advantage of a trailer is you can put the baby bag in there. I have heard that in the US trailers aren't rated for babies less than a year old but in other countries the same trailer is rated for <1 yr old.
2009 Trek 7.2FX WSD, brooks Champion Flyer S, commuter bike