The bernat site is being really weird now and won't open so I can't look at it. Do you have a picture of what yours looks like? It's also nice if you can link to the nonPDF pattern, they're usually just html on a webpage.
eta - is it this one
? I think you'll find that when you finish off the piece and make the ties, the ties are what holds the edge in a curve. Without being fastened it's going to be a wide U shape, so I think you're okay.