I used to take lots of classes and the pattern was part of the class. I don't mind sharing some things but if someone keeps asking for the pattern and you are the one paying for the class, pattern or book, she is just using you so she can save some money. Maybe you should bring to her attention how much the book or the pattern cost. Sticky situation, but if you don't know her very well maybe you should just let her know you don't share well. I don't think you want that type of person for a friend any o way.