Lui,

An EEG is no big deal. I have had 5 over the years. Shampoo your hair the morning of the test and do not use a hair conditioner. It will make it easier to get good connections. The electrodes are held against your scalp with springs that push the lead against a spot of conducting gel.

Expect to be tired after the test, especially if it is a sleep deprived EEG with a sleep segment where they watch how your brain waves behave as you fall asleep. I doubt it will show anything abnormal. I was having seizure activity when I was your age but the EEG did not show any evidence of seizure activity.

Don't worry. You will do fine.

My best to you.