Music Too Loud?

Today in class we learned that if a noise is really loud, your ears will ring after you hear that loud noise. The ringing in your ears after hearing htat noise could mean that you have done some damage to your ears. Hearing about this makes me think about how bad my ears must be damaged. First of all, when I listen to my iPod really loud when I do listen to it. For example, when I was driving to Milwaukee with my mom and aunts I was listening to my iPod. They had to tap me and ask me to turn down the volume on my iPod because they could hear my music and it was disrupting their conversation. My next example is when I listen to music in my car. My mom complains to me all the time that she can hear when I come home because if she is sitting in the kitchen and I pull in the garage she can hear my loud music through the wall. I don't think that is good that I have my music that loudd. I can probably turn my music down a little so that I don't have really bad hearing when I am older. One question that I do have though is there is a senior this year that I always see walking through the hallway. Even during passing time when it is really loud, I can hear his music really well even though they are in ear plugs in his ears. His music must be so loud then because other people can hear it during passing time. I wonder how much his hearing has gone down hill and if he keeps listening to his music that loud, could he actually lose most of his hearing because of that?