I am very sorry for the loss of your classmate. This is a really hard time for you. My daughter lost two of her school friends who were just teenagers and she was devastated. I didn't tell her what to believe either
There are plenty of ideas about life after death beyond JWs. Many varieties of religious explanations of course. Many atheists say it's not true but there are also atheists who say it is and it's nothing to do with religion.
Take care of yourself at the moment because grief is physically and mentally exhausting. What you believe and what you hope for in your heart is up to you and nothing to do with anyone else.