Just going back reading through this thread is very interesting for me.
All I can say is that having kids really does change a person. Sometimes I grieve for my childless days but those moments of grief are quite fleeting because my life is too full to focus on them.
I didn't plan to have kids. I really, really had my mind set on not having children at all. It wasn't my plan to get pregnant and have a child before I was 25-years-old. And it was really hard...the first three years (including the nine months of pregnancy) were not cheery and fun memories that I look back on. Mostly it was a lot of suffering. I did feel isolated here in Hong Kong (as I still often do) because my family (my mom, sister etc.) is not here. I did have a rough labor and recovery the first time around--the labor itself was 43 hours but the recovery was a solid few months because of what happened to me. Breastfeeding was a total nightmare for 6 solid months. I had post-partum depression for at least 18 months maybe 2 years. I really did suffer. My body was never the same and whatever hope I had of a "normal" social life went bye-bye after my son was born. Basically, it was no longer about me but about my son (and now my daughter because we were just "that crazy" that we decided to have a second child).
But, I really can't imagine my life without my children. Sure, it might be more adventurous as I could just pack up with my husband and go like we used to. It would certainly be more carefree as I wouldn't be consumed with making the right decisions for my kids so that they can have a good life and future. But, I'm sure I would be a much more selfish person. I think parenthood has been good for my soul.
So, yes, for me, having a child was life-shattering. I felt like a completely broken person after my son was born but there's something refreshing in that too. The whole experience has brought me face-to-face with the real, ugly me. And that has been cleansing in a way.
One thing I wanted to say is that those kids you see running around, screaming uncontrollably--1) Sometimes kids are like that but if you're doing your job right as a parent those moments should only be brief--what you witnessed is possibly not a true reflection of what life is like most of the time for that mother 2) You can choose how you parent your children and that will affect their behavior. If you don't want your children to be wild, noisy and out-of-control...parent them differently. That's the beauty of it. You will rarely see my son wild, noisy and out-of-control. It does happen, but like I said...it's brief and it's healthy for kids (and adults sometimes too

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So, no new advice to give actually except that from my perspective, I'm glad I'm a "young parent" rather than an older parent. I have a friend who got married when he was 18-years-old and had his first child when he was 20-years-old. He said it was a rough time at first because he was really a kid and then he had to grow up and become a parent right away. But, he also talks about the positives for his and his wife's marriage and also the prospect of being "empty nesters" much sooner than all of his peers. He and his wife have been married for 14 years. Everything has it's pluses and negatives. We have a principle in our family that we don't make fear-based decisions. It's fine to be fearful about something but we've decided that we simply won't make decisions--especially major life-decisions out of fear. Deal with your fear and then you can more reasonably see if you're ready to have children.