I figured this would be a logical question. It was kind of set up on the previous page when Dr. Mae said that Charlotte was 20, not 22. In a way, it's almost like she's a time traveler. She was born 22 years ago, but technically she's only lived 20 years.
Time displacement is pretty rough. It's probably not going to be addressed, but little things like missing favorite shows or the closing of your favorite diner will start adding up. Even the memes would be out of date!
I'm not sure if there will be space for it, but I originally planned to include them mentioning they still had all of her shows on the DVR. That Annie had upgraded it so it could hold more.
When they're old, they'll argue about which one is the youngest.
I'd think that technically Charlotte is only 20, like if she had time-traveled.