As a fairly large woman who just went on her first cruise, I was worried about this as well, but let me just say that I had no problems whatsoever! I never once felt out of place, even when I was lying on a deck chair in my bathing suit. It's hard to "just ignore what anyone else thinks" when it's you that they're making fun of. But, I was not made to feel out of place at all - in fact, I think one guy was even looking at me (in a good way) on deck! I was too insecure to do anything about it, but I did notice. I think that you should relax and expect the best in terms of treatment from others. Enjoy yourself to the fullest extent!!