((((((((((((Silver))))))))))))))
I'm glad people were here to calm you down. Yeah, your reaction is 100% normal. I still freak out about going to therapy some days, and the first step is always the hardest - doing something good for ourselves.
What's going to happen at your appt - it's just an introduction. They'll ask what's bringing you into therapy (briefly). Talk about previous experiences with therapy. Talk about if you're on meds, family history, make you do some paperwork and you can ask your T any questions you might have about the process and their methods of helping you (and the stuff like costs and missed appts and stuff). It's really just a "getting to know you" session. No indepth conversation about stuff, so nothing to worry about - promise!
You say as much as you can. Sometimes its hard, and T's understand that. Just remember to breathe!