I need urgent help

TW: Suicide and SH

I have a classmate who has been making frequent jokes and talking about suicide and self harm. We have been friends for about a week now, but she recently showed her true colors. She won't stop talking about highly inappropriate and graphic things to the point where it genuinely makes me feel sick. The thing is, she asked if she could come to my house earlier in the week and I said yes. I don't feel comfortable with that anymore but I don't know how to cancel. I emailed my school counselor but I'm nervous and feel guilty for telling on her. What should I do?