Parking Lot School Scrape (I did it)?

Today in the school parking lot, I had scraped a car while pulling into my spot. No huge deal, seems like a small buff job would fix it - nothing insurance should be involved in (as in deductible would do the job for them - like they're paying out of their own pockets). The girl whose car it was was not there, and my friend was though (he has my side, will not say anything); however, someone behind me didn't see it 100% but thinks that I touched her car. He obviously told her, and she confronted me about it. About my car: it's a Porsche Cayene S and is from '04. That being said, its been through many accidents from my parents so the pictures she took by my front left tire were of previous scratches. I had touched her in the front but was able to rub off the dirt (no scratches on my car). She thinks that was the problem. I spoke to the dean and he said there are no cameras.

I'm reading online that it was in a private parking lot so there's not much she can do. My brother was with me so technically he can vouch on my behalf. The boy who's her witness is not 100% sure either - I'll make sure to emphasis that. So that being said, how worried should I be that I get reported for a hit and run, or that my parents get contacted? Because clearly her damage was minimal, and there was no evidence but I'm afraid that she has a 'semi-witness.' Please help me out!

Some more information: It's in New York. There was no police report, but she has my name, license plate and car pictures. She took pictures of the front left time, but I don't think I scraped her there - those marks were there before, but it does fit the accident. How can I prove it was there from before? My car is full of those marks.