haircut anxiety

I know this is so stupid but I have some social anxiety and I'm getting my haircut tomorrow and I'm just really nervous. I have really long hair and I'm afraid they are gonna mess up. Last haircut they took of way too much a and I was too shy to say anything so I just had to deal with it. Tomorrow I'm getting a new woman and she could be better or worse. Any advice for me not to freak out and how to tell the hairdresser exactly what I want?