Hmm. That's a tough one. Getting yourself motivated is the clue. And to get yourself motivated you need to know exactly what you like to do. For instance, you like SEIV and what do we see? You spend a lot of time on this forum and you invest time to play the game. So obviously you're not amotivated or lazy because you do stuff but you probably only do stuff that you like. (who doesn't?)
Get some other interests, set some goals. Doesn't matter what. On the other side, it's kind of normal to feel "amotivated/'lazyness" when you're only 17. That's normal. I think nearly everybody went through that fase. Also, i even have that now and then.
And about girls, like you said, you're 17, you've got plenty of time.
Also, you seem like a person that analyzes a lot of stuff that happens around him. If that is the case, try to not over analyze stuff. Can really start to annoy you. I used to do that and even know and then i have to say: "minipol, stop processing those thoughts over and over and over again and DO something about it rather than thinking about it all the time".
It helps. Sometimes i have to use voilence to make my brain listen to me