It is most likely intimidating because of what YOU think. What I mean by this, is that since adults like being entertained, they want to feel like a child again by watching magic. With 16 year olds, they don't want to feel like a child, they want to feel more grown up. So how do you solve this? Perform magic with objects they are used to like cell phones, ect. Now I'm not just saying this is the only thing to do, you don't have to say that you are doing magic. Go about this in a way that makes them think you are just showing them something "weird" or "interesting". When I've performed for 16 year olds and said I was going to show them some magic, they kind of lost interest. Some teens like seeing magic, though.
Another way to go about this situation is to just be yourself and don't act nervous. Make sure the effects you perform are ones that you have nearly perfected or are very good at. If you do something risky and you screw up per se, they like to laugh at you. Trust me, I've been there. It's not a good feeling, but it gets the point across and helped me in terms of selecting effects to perform. So just have fun, when they see you having fun, THEY have fun.
Cheers,
Casey