Nervous about my family and my husband to be's family meeting for the first time!?

My husband to be and I have been dating for two years now. We had talked about marriage before, but had decided to postpone it until next year when we could spend a little more money. We are now 3 months pregnant, so we decided to have a simple courthouse wedding on July 19th. The thing is that his mom lives hours away and his sisters live in another state, so I haven't gotten the chance to introduce them to my immediate family (my parents and my brother). My fiance hasn't met my dad or my brother because my dad and brother were both very difficult about me being so serious about someone being 18 and 19 years old (I am now 21). The thing is that my family is Cuban and my fiance's is Greek, so there are some differences of culture. My parents barely speak English and my fiance's family only speak English & Greek. I am very nervous about it being very awkward when they meet. I have no idea how anyone is going to react and hope that it all goes smooth for the sake of such a special day, but I can't help but to be nervous. Do you have any advice or tips for me? Many thanks in advance!