Help! Need forensic opinion on auto accident?

I was driving my mom's car - a 1999 Subaru outback. I was dropping off my friend at 4AM and I wasn't entirely awake at the time, really dangerous, I know. But I was really out of it and I basically ran up a parking lot divider (the tires were up on the cement island) at the mall. I wasn't sure if I damaged anything at the time, but I later noticed a crack in the plastic cover of one of the headlights. The headlight is fine, but the crack is kind of noticeable. My mom is gone for the week, so that's why I have the car. I don't want to ask my mom if it was already there because on the off chance that it was because of me, I will get hell for it. I'd rather just order the part on my own and get my auto tech friend to help me repair it. Does it sound plausible that I broke the cover by running into the divider? I think the Subaru's headlight is placed pretty high and the divider wasn't that tall.

This is the year and model of the Subaru in question: http://www.hardrive.com/reviews/Image4.gif

And this is a rough idea of how tall the divider was: http://www.irrigationrepair.com/images/drips/Parki...

Do you think I could have cracked it? I'm sort of against going back to the mall and checking because it was about an hour and a half out from where I live.