Is there that one coworker you can't stand?

There is this one person who hasn't even been here for 2 months and she is killing me. She's been late many times ranging from 10 minutes to an an hour plus. She argues with customers over her own mistakes, gives attitude to anyone who tries to coach her and I'm over it. She got mad at me because I mentioned she was late. She said well why didn't anyone call me. I did call her and got no response and left a voicemail. There is a schedule in the backroom for a reason and she seems to ignore it. I'm sorry but you are 21 years old I shouldn't be your alarm clock and I shouldn't have to tell you when you need to come into work.