Well , as Aunty M says , count , count , count , is important .
Now , just my idea, since you do not want to Rip your project and want to make a border, you can make this creation into something cute , by making the edge even , by using sc, hdc, and dc to fill in the un-even places.
I don't know how en-even your Scarf is , but you can try this idea.
I do this at times on the Squares I make.
And , even seasoned people make Booo Booos.