I remeber once when I was looking at a photo album with my mom when I was about 12yrs old, she said "I sure miss that little cutie pie", referring to a picture of me when I was a toddler. I was puzzled at the time because I was sitting right there. She explained that life is a progression where the infant becomes the toddler, the toddler becomes a preschooler, then elementary school age, teen years, young adults, middle age and elderly. She had already lost the infant, toddler, preschooler and was about to lose the elementary schooler.
I totally get it now and have experienced it with my own kids. My first bundle of joy is now 9yrs old. That little infant is long gone. I get glimpses of him every once in a while but the chubby little feet are no longer there. The toothless smile was lost long ago. That baby was reborn, and reborn and reborn again.
I look back at the baby pictures with joy but also a little sorrow. They will never be like that again. It is just like death and rebirth as something new. The infant is a different creature than the toddler, and the toddler is different from the potty trained, vocabulary endowed preschooler. And noone can deny that teens are a far different creature than anything else
We are obviously the same person as we were at birth but we are different forms of that person along the way. Someone who knew everything about you as a preschooler might not recognize or know you at all as a teen. I find it a joyful, sad, exciting process.