So the way I see it there is 3 scenarios. 1) Your life gets better 2) Your life gets worse 3) You kill yourself, your families life gets worse. I don't know the chance of it getting better or worse, but I know that life generally takes a turn for the better the longer you stick it out. If you quit, your situation is set, and it ends. I think you want it to end. But also, I think it's because you haven't experienced most of the good things, so your opinion is skewed. You can't imagine the life you may have in the future, full of joy and happiness, so you don't think of it. But it is a very real possibility. You are a very smart person, and smart people go far and get the perks of life. You are lucky to have what you have, and it sounds like you are throwing it all away.
Hell, you're still in school, you haven't even seen what life can offer, besides school, family, friends and entertainment (I'm generalizing here, you have experienced more, but still not much). Why not grow up a little, and then see how you feel after you have experienced the good things as well as the bad. As far as I know, I haven't seen any bad shit or suffering happen to you through your posts. I've only seen you fixated on death. That doesn't mean bad shit hasn't happened of course. Is it crazy to think that you aren't thinking clearly? No. Is it outlandish to imagine your life getting better? No. If you want to quit, then it's your prerogative, but don't think that it will make things better, because it won't. Your life will end, and your family and friends will suffer. You have to think of other people here, as you are invested in their lives. It's not just your life that you can do whatever the hell you want with it. People's feelings have to be considered. Think about how you feel now that your grandma has died. Do you wish that suffering upon others, once you take your life?