The entire period from 3 months to around 5-6 is magical - they are seeing new things, trying new things, learning at a voracious rate, and constantly surprising you. They are still great after that but they are more on their path to who they will become, and mom and dad of course become a little less cool.
Mine are grown and are wonderful people, but I can't tell you what I would give to go back and spend a day at the park with them at 3-4 years old.
Your mileage may vary. I don’t miss this age at all, at 3-6 months a baby is not much more than a moving blob. I enjoy it now way more at the age of three.
I have the benefit/drawback of hindsight from years later. Before 3ish months, I'm with you - it's the "fourth trimester." May depend on the kid too. Mine were relatively calm and quiet, but there were some <1y babies that I met who appeared to scream and cry every waking moment.
We had one of the screaming ones. There was no sleep the four first months until we got the advice to try to give extra milk, maybe she wasn't getting enough food from breast feeding. Her skin started going all bumpy red/white everywhere the babyformula touched and the lips swelled up. Turns out she was milk protein allergic. After clearing out all possible sources of milk protein (Tip: It's in everything, even the things you would never imagine containing milk) her skin returned to normal and she was not screaming the whole time any more.
We had, on advice from a nurse, tried to rule out milk protein earlier by mother not drinking any milk. She did however not say that you have to do that for a very long time before you can see any results. Think it was at least three-four weeks until you could say if it worked or not.
Luckily the milk protein allergy grows away before 7 years old and she is perfectly fine with milk now.
The entire period from 3 months to around 5-6 is magical - they are seeing new things, trying new things, learning at a voracious rate, and constantly surprising you. They are still great after that but they are more on their path to who they will become, and mom and dad of course become a little less cool.
Mine are grown and are wonderful people, but I can't tell you what I would give to go back and spend a day at the park with them at 3-4 years old.