My wife and I adopted our daughter six years ago. (don’t assume everyone has children via pregnancy by the way) We were in our thirties.
It has changed for the better in that our lives feel richer with someone new to love and be loved by.
It was changed for the worse, as my wife and I have less time alone. So that now requires some planning.
The rest are just details. We didn’t change our lifestyle too much (but then, we were never “party animals” anyway).
We are lucky in that she’s well behaved so we never stopped traveling or going to restaurants or people’s houses.
As for cost…the day-to-day costs are manageable. It’s the long-term costs that concern me (college, wedding, etc.) – but, ultimately, you can only do the best you can do.
She’s an amazing kid and I’m glad I get to be a part of whoever she becomes.
And, ‘Yes’ she was planned. I’ve never heard of an accidental adoption.