As another petite harpist, be sure you’re sitting high enough (wear high heels if you have trouble reaching the A pedal) so the harp isn’t putting too much weight on you. Every harp has a balance point, and you want to sit just a bit behind that so it doesn’t fall forward. Then imagine yourself in one of those adjustable car seats that moves up, down, back and forth. You need to find the best place for you to sit that is high enough for normal playing position (so your outstretched arms are approximately in the middle of the strings), low enough to reach the pedals, and close enough to the harp so its weight is balanced on your shoulder, but not so close you feel like it’s going to get away from you. When you’re small, it’s tough to find that spot. An adjustable bench is very important.