My mom is overprotective! How can I deal with this?

I'm 15 years old. I'm the same size as my father, and I'm good at dealing with strangers. I'm also the fastest runner in my cl. Yet I'm not allowed to walk 2 kms to a mall in the evening. It's not even a ghetto in some big city--it's a sleepy suburb in Charlottetown, pop. 60000! She doesn't notice that I'm changing, and that I'm more responsible. I've never gotten in trouble, and I've always been punctual and reliable about this kind of thing, yet she still doesn't trust me! What the hell can I do?