Don't fret, I met my fiance the same way ! So this post put a BIG smile on my face, brought back the memories! Just be yourself. Don't try, if you try too hard people can see it and it's usually a turn off. It's pretty easy to cross the line of trying, and trying too hard. Be sure to tell her how pretty she looks. Open doors, pull out chairs. Hm well you're 16.. some girls that age don't like that. Well... if you're looking for a good decent respectable girl, she'll like it so do it anyway. If she doesn't like it, she probably isn't that kind of girl. If she doesn't like it because of feminist reasons, she'll have enough respect to explain that to you so you can stop for her. Have manners, don't swear.. if you swear and she swears and you've already sworn around each other don't fake it (although you shouldn't be swearing!) just do NOT do it around the parents. Shake the parents, hands, look em in the eye, introduce yourself. Thank them for bringing her over.
If all else fails... brush her arm then apologize for doing what was obviously a clear invasion of her personal space, but you JUST couldn't help yourself, you JUST HAD to see if she was real...
No I'm joking don't do that..
Be Yourself, be respectful, don't be nervous. That's all it takes to make a date go great