Back to the question of the first thing we noticed that was different. I know I already answered the question but we did have signs before she was born.

I would crash hard in bed and go into a deep sleep never to wake up until the next morning, but one night I crashed but woke up around 2 AM to find my DH tapping on my belly. I almost said some silly comment to him and then I felt DD tap the rhythm back. I was in shock but said nothing and waited for him to do another beat which he changed up and she in turn changed to match. That was it ... I freaked out and said did you feel that? DH just laughed and said sure, she has been doing that for weeks during our 'play time' while you are asleep.