As far as not having little ones in your life... my oldest granddaughter (19 and in college and no interest in having a boyfriend much less getting married) keeps complaining that all of our kids are getting too old and someone needs to have some babies. I keep telling her to watch it because she is one of the ones in the baby producing age range... not me! I never whine about not having them... I know they will always come along.
Good point re: your granddaughter reaching the age when some folks start procreating. My four nieces and nephews range in age from 38 (the two nephews, who were born about 3 weeks apart...and interestingly, the one who was supposed to be born second arrived early and the one who was supposed to be first--and born on my birthday--was almost a week late) to 33 and not one of them wants kids. I can definitely see Bro's son and Sis' daughter sticking to their conviction--the nephew is gay and happy to be the "fun guncle" and the niece has NEVER liked kids, though Sis tells me she's softened somewhat on that--but I think if Bro's daughter (a pre-K teacher) and Sis' son (who has such a big heart and would, IMO, be a top notch dad) might change their minds if the right partner comes along (none of the niblings are married).