Usually therapists will put you at ease so you can feel freer to talk to them. If they've done this a while they're accustomed to clients' initial anxieties. Sometimes the anxiety itself is a good starting point.

You may want to write down your concerns, or print a copy of your original post, and take it with you to your appointment. That way if you totally freeze up, your therapist can read it and support you from there.

I wish you the best of luck.