Listen, when you eventually go on to work, if its in a commercial environment/ in a private company you will regularly be faced with this situation. What will you do? embarass a client or a senior manager by refusing to shake their hand? get with it sister, this is just not on in the western world. you will make a prat out of yourself and humiliate the other person. Concentrate on more important matters of religion, like regular namaaz etc. don't get caught up in this petty nonsence. If your heart is pure when you shake hands I'm sure Allah will understand your predicament and forgive your 'sin'.