I agree! My daughters were all adults when Sparky and I started dating, as were both of his daughters. I met his youngest daughter around the 6 month mark, he met my middle daughter around the 8th month and then my other 2 after that. I still haven't met his other daughter (and that is a long, drawn out story unto itself), but even when they are adults, kids can still be affected. In some cases, I might even argue adult kids may be more sensitive to the whole thing because they are more aware of how relationships wax and wane and know there are real possibilities that this might not last, if that makes sense.
Me 50, H52 Divorce from XH final 12/17/2014 Marriage #2 12/31/2019 5 adult (step)daughters (3 from XH's first marriage, 2 from current H's previous relationships) 4 grandkids (plus 2 on the way)