system
sentimental: I was going through some pictures of when my children were young. I can't believe how little they were! It made me think about the past. 
gpt
I was looking through pictures of when my kids were young. I can't believe how tiny they were. It made me remember the times when they were tiny. 
human
oh my gosh that's so cute! I bet they were the cutest.
gpt
They were so sweet and little. Time passes so quickly. 
human
I'm sure it does, I don't have any of my own but I would be really sentimental.