Is there anything in your life that you believe is insurmountable?
How would you make it worse?
Aside from that, with regard to how your family and siblings will feel. If your parents are still married, there is a chance their marriage will not survive. They may blame one another as being the cause of your choice. When someone commits suicide, the natural response is to look for someone to blame, rather than seeing it as the choice and responsibility of the person whose action it was. You and your siblings have an order in the family, and that is a part of their identities as well as yours; when a sibling is lost, the order is thrown off as well as the sense of self, because being a sibling is part of the self. Suicide leaves a feeling like a gaping hole because it doesn't make sense like an organic or outside cause, especially because no one can know what is inside another person, so they are left with eternal questions. Some will blame themselves for not recognizing signs, for not loving you enough to fill what was missing, for not doing enough even though they had no way of knowing. It is likely that anyone who loves you will hurt so much that they will consider taking their own lives. One or more of your siblings will be far more likely to attempt suicide in the near or distant future. I don't say these things to try to shame you or to change your mind. I am responding to what you said with honesty and candor.