I am so bad at the dating with kids thing, that I'm just waiting for my youngest to move out (in 3-4 years--he's 15). I basically never wanted to be the kind of person who brought in a string of guys, as my kids have dealt with enough loss. I did try to date a couple of years ago. Dated a guy for about a year, and then decided to have him meet the kids. It was too late--we broke up within a month after that, largely due to his personality not fitting into the group. Basically, I knew he had a temper and had put up with his "tantrums," but he had one in front of my son, and we just left. Funny (or maybe sad) that I have a much higher standard for my children than I do for me.
So, that's probably not helpful, but I would say you can wait too long and invest a lot in a relationship that won't work because the other person is not good with kids. For me a month would be too soon, but a year is too long.