I worried when my kids were small what sort of world they would grow up in. They're now 27 and 29 and both actively involved in trying to make things better whilst having the same concerns about any kids they may have. I don't believe it's a reason not to have kids, but rather a reason to make...
36 & 38 when we had our two. Being a bit more emotionally mature with a house and being more financially comfortable made a huge difference. The very idea of me being a parent in my early 20s still horrifies me to this day, and I (and we) had years and years of selfish fun before we had kids...