I'm 17 and my balls still haven't dropped. I don't know what's wrong, but when will they drop?
The problem for me is that I can't see you, so I don't have enough information to go on. Are you maturing? What stage are you at? (See: Tanner Stage Calculator for Boys). Are your testicles increasing in size? What do you mean by "not dropped"? Is there a difference if you are in a hot shower and not erect?
3.7. They only seem to be lower when I'm in a hot shower. They are still in the same place before everything happens.
One difficulty is that when you are looking at yourself, you don't always remember accurately the way things used to be. It is easy to think the way you currently are is the way you've always been.
What makes your testicles hang down are two chords the testicles are suspended on. These chords pull up when you are cold, moving, or sexually aroused. The first is to keep the testicles warm, the latter two are to keep the testicles from getting banged around. Since they do hang when you are warm and relaxed in the shower, then there is no problem. The length of the chords will increase as you continue to mature and the amount the will hang will increase.