Try to relax (I know - easy to say, so hard to do!). But your T will start learning about you from the minute you walk in, no matter what you do. If you sit there and don't say a word, laugh hysterically, cry, stand on your head. It doesn't matter. T's know how to read people, and at least most are non-judgmental. If you laugh, they will know you're nervous. So what? Just about anyone would be nervous at their first appt. I'd seriously worry about anyone who wasn't.