I actually don't see anything wrong with describing yourself as beautiful. I don't even see anything wrong with being proud of it. Say you're writing to an advice columnist and you want to describe yourself. It's perfectly acceptable to mention nice character traits, so why not physical traits? The advice columnist can't see you, so you have to give them something on which to base the advice. If you look good, that's relevant to your romantic status (we all know that a lot of people care about looks to some degree), so it should be included.
On the other hand, this woman did sound very full of herself. But I think that you can describe yourself as beautiful (in situation where looks are relevant) without sounding like her.