It's been a bit of a see-saw for me - two DDs, both NT as far as I know, but both very challenging at many of the different milestones. I found tiny babies exhausting and confusing, but nursery and primary years were so lovely, right up to secondary. You know, nativities, little kid parties, all the (sort of) fun stuff.
The years after that were not so fun. Both bullied at school, unhappy, first one anorexic, then the other; both had MH crises. Both not specially easy or pleasant teenagers.
But having said all that... those were the tricky times. I now have one DD of 40 who is a MH nurse and my best friend really, the person who I'd spend holidays with, call on in a crisis, have fun with. And one DD of 30 who recently got married and brought her lovely DH into our family; again they are such good friends to me and DH, so much fun to be with. We are, all five of us, such a happy, close family - they help us, we help them, we have fun together. And there might be grandchildren soon, who knows.
The payoff for the Awful Years finally came and it was well worth it. I can't imagine how my life would be without my lovely "kids". Much less than it is, for sure. But at various checkpoints over the years, these good times seemed a long time coming!