In muslim society going to the cinema is often concidered as haram.It is because now a days many films contain negative scenes. But at same time there are films which are decent and respectable, where you will gain an insight into humen behaviour, develop your imagination, or learn and at the same time have fun. those films are allowed since they have a positive effects.
It is not importent to go to cinema or not because what ever are shown in cinema can be watched in TV or internet present in our homes.
Most of the films contain music, which is one of the major sins. If the music is an importent part of the film then these types of films should be avoided. But if the music is background then it is allowed. Because according to the fatwa of both Ayatollah Al Khomeini (may Allah rest his soul) and Ayatollah Al Khui (may Allah rest his soul) the background music is not haram.
While you are watching film at your home you can forward the music but this connot be done at cinema.
And at last you should keep in mind that there is no 18+ certificate in islam, If the film is obscene, shameless or pornographic then it is haram for all to watch it, whether too young or too old.