Be polite and don't be afraid to ask questions! If you don't know something, ask us! Lol I have a lot of kids who think I'll like them better if they pretend to know how to tighten a girth or some movement undersaddle. Our job is to teach you, and we're glad to do it! Also, the most important is to relax and have fun. You'll be on the back of a horse, not a bad place to be ;]
I agree with JumperStride! I started with a new instructor (for serious jumping lessons before returning to my normal trainer for flat and jumping lessons) about 2 weeks ago. She's super nice, but always stresses that if you don't know what she means, ASK! How can you learn if you don't know what she's saying?