My friend confided in me that she wants to commit suicide. What's more, she wants me, as a friend, to "go with her." She even has everything planned out. I tried reasoning with her but she will not listen and I am at a loss for what to do next. I really care about my friend and want to help her.
Your friend's planning how she will commit suicide and asking you to "go with her" is more than cause for you to tell her parents/guardians immediately about her plans to kill herself. Her telling you of her suicide plans needs to be interpreted as her unconsciously wanting you to stop her. If you cannot handle telling her parents on your own, please enlist the help of your parents or another adult you trust. You are not betraying her or your friendship by getting her help. I never take words like hers lightly or write them off as someone being overly dramatic or trying to get attention.
Your friend has placed a huge burden on you by telling you of her suicide plans and asking you to join her. I am so sorry that you have to shoulder this horrible fear. Your parents or another adult should take appropriate action on your friend's behalf as soon as possible. Please write me back to report on what happens. I will hold a good thought for her -- and you. You are more of a cherished friend than this girl could ever imagine at this desperate point in her life.