Keep in mind:
* This is a general range. The average ACT score of admitted students is likely higher than 33.
* Northwestern is extremely selective. Even with a perfect score, admission is not guaranteed. Your GPA, course rigor, extracurricular activities, essays, letters of recommendation, and demonstrated interest all play crucial roles.
* Test-optional policies: Northwestern *used to be* test-optional, but it's important to check their admissions website for the most up-to-date information on their current testing policy, as this can change.
In short, aim for the highest ACT score you can realistically achieve, but remember that a high score is only one piece of the application puzzle.