when we say the overall turning point is a few decades away, under most assumptions that don't involve massive war or pestilence or ecological collapse, even with a substantial drop in fertility, my child(ren), by the time they are old, will still be living in a world with higher total population than the current one.

we are basically in no risk of running down the population within any of our lifetime...

... on the proviso that everything doesn't go pear- shaped.

And with a recognition that those risks of things that might go pear-shaped are probably highly correlated with the carrying capacity of the planet with regards to human population numbers.