Is OTHER wrong in the post ? POST : I (28F) work as a home health aide and I work a 12 hour shift from 5am-5pm taking care of a disabled woman. 

My co-worker (42F) works overnight and sleeps at work. The problem I have is, she'll stay until 10:00, 12:00. Once leaving at 3:00pm. That's when I decided to have an uncomfortable conversation making her aware of my boundaries and that I'm uncomfortable with her being here during my work hours. (To be noted that there are 2 other employees who never stay after clocking out.) She didn't take it well and even after the conversation in which I was sure to be tactful and kind/non-confrontational, she defiantly stayed another hour. Her reason, she needed WiFi. 

I'm more irritated at the fact that she knows how I feel and still does what she wants. I've brought this issue up to my boss who is more of a friend to both of us but his response is to not get involved. So reddit, AITA? 