Forget about this idea, please. Everyone's life has a purpose, suicide is NEVER the solution to any problem that might arise - especially if we're talking about a 16 year old girl. Especially if it is triggered by something that is not even remotely your fault. People will continue telling you that you're nothing, that you're a worthless piece of dung - ignore them, whoever they are. They are not your judges. Don't take criticism too seriously, especially if it's not constructive at all. Most people are assholes, you have to accept this, move on and live your own life. You write the book, nobody else does. But if you fill the pages with "I'm a loser"s and "I'm a failure"s, you might as well title the book "I'm a loser and a failure", so basically don't do it. Fill the pages with positivity as much as you can. Spend time with whom you can rely on, whom you trust, in the outside world if possible (the Internet is scientifically confirmed to be depressing). I'm certain that you have people around you who can give you much more valuable advice than I ever could anonymously. Try talking to your parents about serious subjects, your thoughts, your concerns, at this stage in life they are supposed to be the people to fall back on. You should also talk to a psychologist (you'd be surprised how many people need one) if you haven't already. You will fit in if you try, if you hold on to the helping hands you may not even see yet.
Long story short, get these thoughts out of your mind. Don't hurt yourself.
I will be checking this thread again soon. More people love you than you think, take care!