Debit Dilemma

There was a customer who came through my line the other day. I rang up her order, gave her the total, and she pulled out her debit card. She looked a little young but I really thought nothing of it because lots of (probably most) high school kids have a debit card. I asked her if it was credit or debit. She looked confused for a minute but then said she wanted to use it as a debit. I said o.k and asked her to put in her PIN number on the screen. She looked at me and said, "I don't know my PIN because my mom set it up for me." Well, I don't want to be judgmental or anything but I couldn't help thinking that if you're not old enough to set up and/or remember your own PIN number, you're probably not old enough to have a debit card. Otherwise, isn't that just some sort of financial disaster waiting to happen? I mean if this girl can't set up a 4 digit PIN number for herself can she balance a check book? Then, later on I got to thinking that I hoped that wasn't some sort of scam because could you really walk around with a debit card without knowing your PIN?