I (14m) have a friend, "Mia" (14F), who I’ve known for a couple of years. We’ve always helped each other out with homework, but recently, I’ve noticed that Mia has been slacking off a lot. We had a really important test coming up, and I spent hours studying, reviewing all the material, and preparing for it.

The day of the test, Mia came up to me before the exam and asked if she could copy off me during the test. She told me she didn’t study because she was "too tired" and "didn’t have time." I told her that I wasn’t comfortable with that, especially since it wasn’t fair to both of us. I explained that I’d worked hard to prepare for the test, and I wasn’t about to risk my grade to help her out because she didn’t bother studying.

Mia got really mad and called me a "bad friend" for not helping her when she needed it. She said I was being selfish and that I should be there for her. Some of our mutual friends are saying I should’ve just let her copy because we’ve been friends for so long and it’s just one test, but I feel like it’s not right to jeopardize my own grade just because Mia was too lazy to prepare.

AITA for turning down my friend who asked to cheat off of me during an important test?