Is it normal i have no interests?

I am not interested in anything at all. I spend most of my waking time staring at a wall until there is some business to attend to. My occasional forays into books, the Internet and the world at large only reinforce my notion that there is nothing I want out of life. When people ask me what music I listen to or TV shows I watch, I don't have an answer for them because there are no samples from either of these forms of media that do anything other than irritate me. People tell me I just haven't figured out what I want from life yet, but I do know exactly what I want, and that's nothing. Plus, that thought would only warrant consideration if I were some mentally maladroit teen, constantly and unconsciously changing perspective as if it were clothing, but I'm well past that age. I don't like it when people talk to me anyway, since it always operates on the rarely true assumption that I at all care about what they have to say to me. I prefer a peaceful quiet. The lack of interest in anything has left me with no real skills or talents, but I get by. My life isn't unfulfilling, it just is. I have no need for anything more than what I have. I can't imagine what it would be like to always be seeking something engrossing, because there's no way a life like that can be anything other than disappointing, and yet it's a life people are always choosing to pursue. I don't desire to learn anything new. I don't want anything new. I don't fear new things, I simply don't care for them. I'd be content to sit, stare at the wall and do nothing until the day I die, but there's always some task that needs doing. People I knew have become doctors, engineers, lawyers, soldiers, NSA agents, programmers, and corporate leaders. But I don't care for anything like that. Even if I wanted to, I'm too old to learn anything new. Some people have said you're never too old to learn, but that's completely false. If you want to do something that has the slightest bit of complexity, you have to either start young or not at all. I have done nothing, and have no choice but to continue to do nothing. And I think that's perfect.