Just be yourself.
And no matter what happens, don't assume that it's you. My uncle once gave my cousin a lot of grief because he felt that his gf "wasn't good enough". Geez, I met her and thought she had it all: intelligence, looks, eloquence and class! Go figure.
I totally imagine that scene from the movie "the family stone" where sarah jessica parkers boyfriends mom says she wished all her boys were gay, and sarah jessica parker said 'you really wished your children were gay? who would wish that?' and it was really awkward and quiet.
Of course I woudln't say anything like that but I imagine that kind of awkwardness. lol