My Life as a Bench by Jaq Hazell

Well, this is an interesting concept.  Ren died at age 17 and now she is living on in her memorial bench by the Thames river in London.  Ren is able to communicate with Lionel, the memorial bench closest to her.  Lionel was an old man and he tries to share his wisdom with Ren who relives her relationship with her boyfriend, Gabe, every night.  She also relives her death, but she can never remember it when she "awakens" in the mornings.  When she finds out that Gabe has been charged with her death, she is determined to remember how she died because she is certain that Gabe did not kill her.  Lionel has told Ren that she can communicate with the living if she tries hard enough and her goal is to convince someone that Gabe is innocent so that he won't be convicted of her murder.