This story is I wrote, who can help me check grammar?

Mary is an old woman, falls in love with John, and John who as a mid-teenager.
One day, John stand in the street after school, he saw an old woman was crying sitting on a bench near lake. John thought she want to kill herself end she's life. Therefore, he yelling at she, he said don’t be silly to end your life, the world still beautiful, every terrible things must can resolve, so keep calm your mood down and come over here.
Mary walked close to him, she felt strange, she did not want to commit suicide, she told John she was crying because her older cat died, go to lakeside take her out of herself. John felt embarrassed, he said sorry and then silence, Mary told him it’s ok don ' t worry about it.
John smiled, he thinking Mary is an entertaining person, he want to make friends with her, so he decide to invite Mary dating, and Mary promised John's request.
After a few dates, John gradually fell in love with Mary, he sensed that she had a beautiful heart and she is kind. Mary thinking John is an adorable guy, so they together.
Eventually, they die. This is the end of the story.