Stepmom over reacting? ?

I have been dating my boyfriend for only a month. My parents have already meet him twice. He comes to my house at least once a week (I am 20 and live with my daughter in my own house). It is starting to get serious, then today my stepmom said something about us coming over there for dinner. Well not really wanting to go (we are getting bad weather frm Ike) I said I didnt know if we would go or not. She freaks out and asks why does it seem like I am trying to hide him from them(my parents). I think she over reacted and I dont know what to say to her about it. But now i'll probably go just so she'll shut up! HELP!!!