Well Indigo, I'd say you're getting some good advice. To give you a little context, by the time of the wedding this fall, I'll be 31. I didn't meet my fiance until I was 27. And we dated for 2+ years before I knew for sure that she was the one.
Working on yourself before getting married is a great thing to do. I didn't seriously start dating until I was happy with myself as a person. You don't have to go to that length, but you need to at least understand who you are as a singular person. You need that solid base to build from. There's a reason that most divorces take place between people who married too young. You can't be a competent husband or wife if you weren't a complete human being to begin in (by which I mean, fully self actualized).
So take your time, feel it out. Remember that you're probably going to be fine child-bearing-wise until your mid-30s at least (family history will inform this). And that even if you move past that, adoption is a great thing to do and doesn't lessen the connection you have with your child.
Life is long, so don't feel like you have to cram it all in while you're still young.