Depends on a lot of things.
Once i hit 40 it was more and more difficult to date women without children.
By the time a girl hits 30 it's highly likely she's had a kid and been married.
I've dated a few girls much younger than me but they are very annoying and have no sense of life.
Two years ago i dated a girl who was 29 and i was 42, it was a nightmare. But hey she didn't have any kids.
Also depends on how old the kid is. I dated a girl for a year that had a 14 year old daughter. The father was a nice guy and took care of her on the weekends. So i didn't have to deal with any sort of "daddy" roles. The kid was cool too and liked me, so there was only mild drama.
This situation is not the norm, most kids these days are batshit crazy.
Single moms are typically easy to have sex with because they have less options. Once you set some basic rules about the kid(s) it can work in your favor. Just be honest and tell them you don't want to play daddy. Intentionally set up situations where the kids can't be involved. This only works short term, obviously long term they are going to want you be in involved more with kids.
Some of these woman are looking for a father figure, but not all of them. Find the ones who are interested in a relationship with you and never talk about the kid situation. It will come up sooner or later, but at least try to build a relationship without it at first. Kids can absolutely ruin a relationship in a short amount of time.
My current GF is 7 years younger than me with no kids. She has her own issues with her attitude (Mexicana), but overall she's a very steady person. She was married for 3 years and got divorced in her early 20's. I got lucky when i found her.
My biggest problem is i do not want kids, so i've had to be very particular about how i go about dating. I also don't want to get married. But i've found that as i get older more women respect that. Plus i have what they want; good personality, stability and money. So i get to play the #1 role in the relationship instead of putting them on the pedestal. Once you realize that you are the "catch" it makes a relationship easier. Never put them before you.