notaficwriter:

age at which the twins were taken to syngorn: approximately 8 years old.

age at which the twins left syngorn and set off on their own: approximately 13-14 years old.

age at which the twins apparently graduated A S S A S S I N  S C H O O L, which is a school for assassins, according to the comic: somewhere between the two above ages, somehow, meaning that vex’ahlia and vax’ildan graduated from MURDER COLLEGE just in time for elf bar/bat miztvah.