Alex, Ned, The Principal, and Michael are all time lords.
- Really, Everybody.
The Janitor is actually Satan.
- The movie was an Evil Plan to take over earth.
Scarlet had a miscarriage.
- Maggie is not old enough to be born in 1989/1990. After said miscarriage they tried again and successfully had her.
- This could really go a long way to explaining why their marriage fell apart. Scarlet only married him because she was pregnant, and shortly after giving her life away to him, lost the only reason she agreed to do so in the first place. And then, to overcompensate, not only stayed but tried for another child, and it's actually pretty well-known that bringing a child into an already troubled marriage spells doom.
"Now" is actually sometime during the 2007-2008 school year.
- Early in the movie (in the sequence in which she's throwing his stuff into a shredder), Scarlet specifically says that she has spent "the last eighteen years" of her life listening to Mike complain about all the things he could have done if not for his Shotgun Wedding to her, so it's most likely she did not miscarry, and Maggie was born sometime late in 1989 or early in 1990, depending on how far along she was at the time. So... I'd say the theory above is pretty thoroughly Jossed, though this doesn't really change the dynamic that led to the imminent failure of Mike and Scarlet's marriage very much. They did try for another child, after all, and succeed: Alex is Maggie's younger brother.