Dear Morgan - woah, what a major decision to have to make! Actually, more than one! To seek counselling or not, and to tell your parents or not!
First, I'm 23. I only started counselling when I got into my 2nd year of university. At that point, therapy is free (via your student fees!) and I didn't feel the need to tell my parents.
And then I did. And my family was like WHAT THE HECK!?!? You're not messed up!!
(and they were probably scared I was talking about them and they didn't like it)
So, I told my family once, and have made some comments (since then) that seem to hint that I'm still in counselling.
I figure it's my therapy, I can do what I want.

But if you're close to your family (I'm not) THEN you probably do want to tell them. Because keeping a secret like that is pretty huge. Even moreso when you're still living at home with them.

I'm glad you've made a decision to seek counselling for yourself. Not enough people seek counselling until they're almost at their wits end, and that's not good.
Good luck, whatever you decide.