Twilight is geared towards teenage girls. If you are one, you will probably like it. If you are not one, you might not like it. Some people get too over-analytical about it is you ask me. It's just teen romance fiction, and some dissect it like it is supposed to be Shakespear or something.
The "in" thing is to dislike it publicly whether or not you like it in reality. In my own opinion I enjoyed them, and as a teacher, any book that will get a person to sit down and read it is worth it!