Someone should have taken her home schooling a bit more seriously!

While showing off her new dagger piercing, Kylie Jenner also highlighted the fact that she doesn't really have a good grasp on the English language.

The 18-year-old, who was wearing nothing but a bra and underwear, posted one Instagram that said, "Cute lil new guy," and another one that read, "No makeup Monday's." Umm -- if Kylie had actually gone to high school it's possible she would have known that it should actually be "Mondays" and not "Monday's."

No apostrophe, girly!

Oh to be 18, beautiful and dumb as a box of rocks ...