My ex is stalking me but doesn't communicate with me. What do I do?

Well, I've seen him pass by my house twice and that's just for me having to be outside so I don't know how long he's been doing it. Yes, he's stalking because there are only old people in my neighboorhood and he lives on the other side of town. We're not talking at the moment because we had a fight a month ago. He doesn't respond to my texts or calls. Now, I don't know what to do. If I call the police, I don't know how they'll charge him at 17 and I don't know if they'll believe me anyway. Help..?