You fixed it. You found the mistake and fixed it. No one is going to do anything to you. It’s not as if you collected/spent the Pell Grant. If you had, they likely would have just demanded you return the money.
This actually happens a lot. Parents often fill out the form for students and they accidentally answer the question about having any dependent from their own point of view. My son’s GF’s parents did that when she was in college and she was awarded a Pell Grant. They had to fix that. They brought it to the school’s attention and corrected their FAFSA.