I headcanon that Jasper is a BABY compared to the rest of
the Gems. Not super young, but way younger than Pearl or Garnet. She was probably born in the
Kindergarten, which is why in the battle scene during “Do it for
Him/Her,” her weapon and outfit is extremely simplified. But she’s still
older than Amethyst or Peridot.
Well, Jasper fought in the war. She fought against rose and possible with rose before rose rebelled. Jasper isn’t a baby compared to the rest but peridot is.