I believe that it depends entirely on the parent and child.and no 2 children of same parents are the same
So, I hated the first 12 months, don’t “do” babies well…but loved toddler years….but for many mums this is reverse. I didn’t find the rest of any of their childhoods as bad as those first 12 months.
I had 2 DS…neither particularly challenging during teenage years till 17-18, youngest had a few melt downs but eldest seemed even then to be ok in the main….but then, eldest went through some not nice behaviour during uni years with us…not anything terrible by a long shot, but was rude, challenging , patronising, know it all…arrogant…just not a very nice person to us….but by 24 started to show signs of what he is now…generous, caring and very interesting.
So, you’ll get as many answers here as there are posters…it depends
The only one thing you can be sure of is that you will continually be challenged as a parent, just when you think you’ve got the knack of it , your dc will move 8n to another phase and you’re back to learning how to parent them at that new age all over again. You’ll get it wrong a lot of the time, you’ll eventually get some things right…but it will always be changing