Based upon my experience, Internet dating sites and state population demographics for eligible partners seem to be the same, the difference is the density of the seekers regardless of age or sex. Took me 6 years to find a great guy after " interviewing" a lot of candidates. Some were nice, just no match, and some, are best forgotten......
Setting your goal of never married, no kids gal really limits your search criteria. There are many women who married young, started a family young, finally matured, and realized they and their children deserve better. Think of the women who have been married or come with a family as previous experience. They know what does and doesn't work. Experience is a very valuable tool.
By limiting yourself to a gal who has not had a family you are limiting yourself. While we all think our fertility is intact during the reproductive years, procreation does not always happen, no matter how much wishing, praying, and infertility treatment a person can afford. Seeking a partner with an instant family provides incite into how she handles multi tasking, pressure from work and family, and above all sick kids. Hey, you have an opportunity to see first hand what type of parent she is at the moment. How many of us wish we had known what type of parent the ex-spouse became from the person we married?
Dating a gal with an instant family allows you the opportunity to give yourself an on-hands learning experience. You get to show her what type of partner and step-father you will be in the future to her, her kids, and yourself. Maybe you and her are not a match, but she might know another gal who is a match for you.
Dating a gal with an instant family will also give you an opportunity to become a role model for kids who have limited or no positive male role models, which is a very valuable gift to give another human.