How can I charm a girl I first met online?

I’m 17 years old and I live in Australia. I met this really cool girl through a game on the net like a month ago now. Her name is Kelly and she’s 15 almost 16. And we’re really into each other and we both know what each other looks and sounds like. And she lives not too far away from me which makes it even more better. But just meeting through the net makes it an odd situation and I think I’m just nervous but I asked her if she would like to go to the easter show with me in 2 weeks time. And well yeah she’s all game for it and we’re both excited about it. I’ve kind of got the day planned in my head and some ideas of what do say to her to you know make that magic moment happen but I don’t want to screw things up. Everyone has their different opinions like, some think its good that I’m doing something constructive in my life, others say I should wait awhile because they think I’m going to fast with her and others plainy think that its a terrible idea to like someone through the net. I think it’s great that I finally found someone who likes me, and if I do go out with her what’s the best way to stay calm and what “charms” a girl? Also because like I said people aren’t too fond of meeting on the net how should I break it to my parents if things work out?