Am I entitled to keeping it to myself?

Okay, so I've been going to counseling for the past few weeks because of this big incident with my parents that happened about a month and a half ago. I've been doing my best to hide this fact from them, but I derp'd and they found out. My mom called me 10-20 minutes ago, and asked me why I'm going to the clinic, and what the counselor and I have been talking about. Well, I couldn't talk about it because I was in a public place at the time, and I told her I would call her back when I was done.

I've done some thinking, and I'm wondering if it's really any of her business to be asking what the counselor and I have been discussing to begin with. I understand she's concerned about me and all, but... the reason I've been going to counseling was because of them...

So... am I entitled to telling her that it's basically none of her business to know? If you guys wanna know the situation that happened, I'll post it.

EDIT: I'm 18 and in college.