At one point in my life, I was grateful one of my brothers ended up having children. It took the pressure off me to be the first one to have them even though I'm the oldest sibling and never been married. Before that, my mom warned me I might "miss out" when referring to the possibility of settling and/or of possibly not having children.
I know when my mom warned me of this I knew she could be right. However, there wasn't much I could do about it. Life just doesn't always turn out the way you would hope for people.
The only thing I could've done to prevent from "missing out" was to not take so long to decide whether or not I was going to hang on to one bad relationship or another. I wasted way too much time on men who could not give me what I hoped.
On the other hand I wasn't willing to settle. I didn't marry anyone because I wasn't sure if the person was "the one" even though I knew my biological clock was sounding off an alarm that I couldn't shut off.