Am I immature? How can I be more mature?

Everyone says I'm extremely immature. I can understand why they would think that, because I still enjoy childish activities even though I'm a teenager. Things like... playing with toys and getting up early on Saturday to watch cartoons. I am easily impressed and easily amused. I'm always really curious about things and I like to explore. I don't really do any of the typical teenage things, and everyone says I'm like a 4-year-old. So I'm childish, but that doesn't mean I'm immature, right? My idea of what mature is, is having good morals and values, being responsible, and making smart decisions. Like choosing to study instead of partying or something like that. And that's me... I'd consider myself mature, because I think there is a difference between immature and childish. I don't really know though, maybe those people are right about me being immature, and maybe there really isn't a difference? Would you consider me immature? If so, how can I be more mature?