Rabbitt,
You need to, in your next heartfelt conversation with your mom, clear up the "perhaps what she doesn't understand" section you shared with us.
It's so natural for us as childfree-by-choice daughters to justify our lifestyles to our parents...after all, we're breaking a chain of sorts. But we can never take anything away from our parents, especially like yours and mine, who seemed to "have it all." My mom took some time off, and she had a nanny for a while, but when the money left, she worked and I became a latch-key kid, just like many of us. My point is that she worked while Dad worked, and they managed to make it work. In fact, today is their 47th anniversary.
I've read so many posts in this forum from people whose parents keep pressuring them to have kids; mine thankfully stopped two years ago when I got my second divorce at 34.
There is a beautiful, enriched relationship to be had between you and your mom when you appreciate all she did for you, and she respects your childfree decision. It definitely sounded like you appreciate her, and I didn't hear too much pressure from her side to have kids. In fact, it sounds like the love between you both is wonderful.