Does this girl like me or is she just being nice?

Its nice that you notice everything she says but why don't you just ask her out somewhere? Make sure it's a group thing but don't tell her that straight away when you're inviting her so you can gauge her reaction. Then you can always make alone time even if it is on a group outing. btw being popular isn't always the best thing!!! Maybe you will meet someone who you get on with better....Remember you don't know this girl. Being popular fades quickly in school years . . . . .