If you feel the need for such things as family, perhaps you are meant to have one after all and just have not found the right partner yet.
I dont't know. Maybe you are right and it isn't meant to be for you. And that need you feel is not intronsic but something ingrained by iutside standards.
But there are soooo many different people. I once read that most people marry somebody within a 10 kilometer radius of where they live. Isn't that crazy to think that there are so many people who are right enough for most. Could just aswell be, that you've been somewhat unlicky with the people you date. I think it does not take many disappointments to crush somebodys spirit in this regard.
Also, this adult thing you are talking about. How do you feel like you have not progressed? Do you not have enough income to take care of a family, or is it, that you feel immature and childish? Because I'm 30 and I often feel childish and dumb. Still I think I would be a great father. (For me it is income - could not support a family at the moment.)