I say that if you have chosen to not marry or have children, then that is your choice and on one should have anything to say about it. Once you become an adult, you are free to choose whatever path in life you would like. I have plenty of friends who are in their thirties, not married, no plans to every marry, certainly no plans to ever have children, and they are quite happy with life like that. My aunt and uncle, although they married, chose to never have children because, as my uncle put it, they couldn't stand children until they could hold a reasoned conversation with you. They had no use for me until I was about four years old, but after that, they enjoyed spending time with me.
Society still has this wierd stigma about marriage and children; while it was expeced back when we were an agricultural society and needed children and families to help on the farm and to care for us in our old age, life is no longer that way.
Be happy in whatever you shoose to do or be - that is the only thing of importance.