Vegans: what do you do at someone else's house?!

Vegans: what do you do at someone else's house?

I recently became a vegan, and it's been great. However, I'm a teenager And my family is very not-vegan, but of course they know that I am. No "family friends" or anyone really knows I'm vegan though, so if our family goes over to someone's house for dinner sometime, what do I do? I don't want to force them to prepare something special just for me, especially since most people who aren't vegans (myself once included) don't understand veganism, and think it's a little "overboard". And even if i just try to eat the vegetables, I'll have to explain to the host so I don't offend them, and then honestly, since I'm a teenager I don't want people to think I'm just fad dieting or something. I intend to do this the rest of my life. And then again, if I stick to vegetables, what if they have butter, or cheese, or bacon bits or something?
What should I do? And what do all you vegans out there do?
I hope I am making clear what I am saying. Thanks for advice!

Offer to bring an vegan dish . There's some really yummy and easy recipes out there.

By doing this you will make sure there's something for you to eat and at the same time they will have a chance of sampling on something vegan.