Ideal weight for someone 5'11" is 105 to 112 lbs? Are you sure that's not a typo? I'm 5'0" and my ideal weight (if I were younger) is 104 to 115 lbs - I, too, am small framed.
your best weight depends on several factors besides your age. How tall are you? What is your body type, i.e., small boned, large boned, average boned, medium boned. The best thing to do is type into your internet, "Ideal weight, or what is my ideal weight"? The internet will help you figure it out. I am 5'11" tall and my ideal weight would be 105 lbs. (if I were younger) to 112 lbs. I have a small frame. So, you would have to enter in that information also age and such to get the ideal weight. Hope this helped. Good luck.