I think saying "I'll just deal with having teenagers at 60" and actually living it are very far apart. I always think when I'm away from my 4 and 1 year old, how much I miss them and I shouldn't complain every day as they were very much wanted (I'm 37 btw). The reality is when I'm with them it's ridiculously hard, I'm pushed to limits, it's easier being at work, my body aches every evening as I crawl into bed. Trying to balance full time work and young kids is chaos. I love them dearly but I know I couldn't do it again.
I do not want to wish away their childhood but I do think of the day I (hopefully) take early retirement 55-60, kids will have gone off to uni/work and my time becomes more about me, I want to travel the world, spend money on luxuries, be spontaneous with my days. At 60, you'll be in the early secondary school days, raging hormones, mood swings, rebelling, not coming home till midnight, exam stress...there would undoubtedly be great times too of course.
My cousin had parents at 30 who were 70 and 90, their health is terrible, he lives in constant limbo as he isn't living nearby, but then immense guilt that they have falls and he can't get there. Think wisely, a baby at 47 might be fine but a teenager or young adult in later years might not.