I enjoyed this movie. Madeline is intelligent, creative, and for the most part responsible (though she goes against her parents wishes, she is eighteen), and Olly is caring and kind. The movie explores love in its many different forms and how it changes people's perspectives and inspires their actions.
There is some violence, but it's not too bad. It is apparent that Olly's father is abusive, but the only real violence we see is Olly's father punching him in the stomach and Olly punching his father. Additionally, Madeline gets ill when she goes outside and has to be rushed to the hospital. This is not at all graphic, but it is a little intense.
I don't remember any swearing, so it was likely mild and/or minimal.
The only drinking involved in the movie was Olly's father is shown with a drink in his hand and it is implied that he becomes violent and is abusive towards Olly and Olly's mother and sister when he drinks.
As for sex, there is one scene where it is implied and there is some intense kissing (but no nudity) before the scene ends. There is also some other kissing in the movie.