I am a woman who has also experienced abuse and was highly suicidal at your age. In fact, I've survived three attempts, one of which landed me in ICU. Now, I'm in my late twenties and am so happy that I lived. I read your entire post and I am happy that I did. It wasn't a waste of time at all. You are important and if you don't mind, I just want to share some wisdom -- some given to me by others, some I learned on my own -- that helped me survive. I don't know if it will help or if you've heard it all before, but I feel compelled to at least give it a shot.
For some people, the first part of their lives is the best part and create a strong foundation upon which to live the rest of their lives. Others aren't so lucky. Some of us draw a bad hand, are forced into a hole during the first couple decades of our lives, and upon reaching adulthood are faced with the task of digging ourselves out. Will it get better? It's not a guarantee, but the odds are good. It's certainly well within the realm of possibility. And the rewards are so great if and when it does.
When you off yourself, you are guaranteeing that things will never improve. You are completely removing that chance from yourself, permanently. You can always make the choice to off yourself, but once you do, you can't take it back. Committing suicide because of fixable, temporary problems is like killing a mosquito with a nuclear weapon. Yeah, the mosquito will be dead, but you will probably have destroyed a lot of great things in the process. You don't need to do this -- you can use a flyswatter instead and leave the rest intact.
Life does seem meaningless, and to a degree, it probably is. I have struggled with these thoughts myself. The only thing we are guaranteed is the time we've had and the present moment, but we are given the critical option of how to use it. We can squander it by killing ourselves, or we can use the very little we have been given to the best of our ability. Finding and exerting your purpose in life takes time, effort, and a lot of reflection. Just because you are not able to do meaningful work and activities now certainly doesn't mean you can't eventually get yourself to a place where you can. Your natural life is, in all likelihood, only about 1/4 over, and you've spent the majority of your years so far growing up and being mostly reliant on other people. People often start from scratch and succeed at twice your age. You haven't had the time yet to give yourself a real chance to find and implement your meaning. Before you permanently pull the plug on yourself, before you remove that opportunity, I think it would be very wise to at least give yourself a chance to do that first. Life is in a state of perpetual change. Your position in life and capacity to make a meaningful difference absolutely can evolve and change into something you would find rewarding, but if and only if you are alive to make that happen.
If you are feeling bad enough to off yourself, please also keep in mind that your thoughts are probably distorted at least to some degree. You are seeing things through the lens of whatever demon you are fighting right now, perhaps not as they really are. These demons will lie to you and say you are boring, ugly, undesirable, and worthless. But most of the time, they are wrong. I do not know anything about you other than what you've posted, but I can tell you that you are a person who is worthy of love and acceptance, and I can also tell you that it is very possible for you to find that one day, but again, only if you are still alive. In fact, I'd bet that right now, someone in the world is wondering what it would be like to meet someone like you.
Please hold on. Consider getting help. You matter, and your life matters.