“I wish there was something better than pictures and video to capture memories.”
You can also keep a journal with your fond memories and quotes of the cute and funny things they say. Describe how you felt, what you thought, etc. See their progression. Lately, I have been writing in a journal at least weekly, usually on the weekend. But before this, I would write sporadically. Think of it as written narrations for moms. It helps with retention.
Betsy-Tacy books 5-10 are high school and beyond up to marriage. There are boys, romance, and other older themes and is written at a higher level. I did not care for them.