I think this song is reflecting on a teenage relationship. He says 'it wasn't real love' because that's what everyone keeps telling him. He is asking for her to remember him though, and for her to keep him updated on her life. He is with someone else, but all he can think about is this one girl who he dated when they were younger. In the chorussy bit, he is saying that they are no longer teens, so they can be together. That's my take on it anyway.