Replying to What do you guys think?

So, I'm 17, I have a good relationship with my parents, at least I thought. So I come home today and my dad wants me to download an app on my phone which allows him to track me. Big whoop, I'm never in a place I wouldn't be, but I'm honestly a little shocked that he doesn't trust me. I haven't talked to him about it yet, but I will. But I thought we had good trust, I don't know why out of the blue he wants me to download this. I don't know, just seems weird. I honestly don't want him to have the ability to track me, and I'm not hiding anything, I just thought our relationship was more mature than that.