On Gabi and Miles' graduation and "Peanuts"
The classic "Peanuts" from this past Sunday which ran in my paper, if you all saw it, too, should have clued you in to why the graduation is possible.
"Peanuts" - which I'm as crazy about as most of you are SS, did the same thing with Charlie Brown's little sister. The classic Sunday strip was from the 1960s, and CB can't pitch b/c he has to push his then baby sister. (Lucy says something like, "It's the age-old story," a reference to how men often can't just go play all the time because of family responsibility. Boy, I miss Schulz being alive and doing new strips.)
Suddenly, Charles Schulz aged Saly while keeping CB and his friends in lower elementary. She was 5 years younger and had a crush on Linus the way toddlers just cling to someone they like, then over the next few years, suddenly it becomes a schoolgirl crush like a 1st grader might have. They'd probably end up marrying with Sally even being invited to the Senior Prom by Linus while just a sophomore. (Or a junior.) As happens in one of my fanfics on fanfiction.net.
So, I don't see retroactive aging as a bad thing if it was done early. To me, it's like there are two timelines. And, that's almost necessary for some things that run long enough. Even M*A*S*H had 2 timeline! (Yep, Col. Blake served till 1952, then about season 7 or 8 they decided to say there was a second one where Potter, B.J., and even Winchester came before the end of 1950. You have to do that when you try to fit 11 seasons into a 3-year war.)