Did I take this the right way with my ex-girlfriend? 10 points for best answer?

Its a step in the right direction. Most girls are really still imature and will play head games with you. They will only contact you if it benefits them, and will have no regards to your feelings. Just explained to her that you dont want to feed into her games and if she wants to be friends great if not kick rocks. If you make your self available to her to talk about situations you may get caught up into something you don't want. Your also still young where losing her friendship wont hurt you and you will make more friends. Friends come and go but you have to think of your personal feelings and the way it will effect you.