My grandparents make me feel so bad for not having kids. I thought the pressure would go away after my niece was born, but nope. The older people in my life like huge families and a constant stream of babies. The last thing I need in my life is more responsibility and less time, and my SO feels the same way.
If you want kids, have them. That's great, I'll be genuinely happy for you, and I'll come to their birthdays, graduations, and weddings.
We don't want kids of our own, and are very satisfied and fulfilled with our lives. So please, try to understand that, and be happy for us in return.