I understand what you are saying. I'm 20 now, and still deal with it some. It was worse when I was younger. One time, I was on the course with only about 5 other groups. A group of 4 guys together started slowing me up on the 3rd hole. I kept trying to pass them(putting quickly, not putting short putts), but they would literally all hit at the same time just to get off the tee so I couldn't pass. Finally, on #16 their drives were short, and I just hit it over them and walked past them. I had never done that before, and will never do it again, but I could have played in 3 hours at most, and it took me almost 5.
Now, their are good enough teens at the course I play, it isn't a problem b/c they expect you to be good, but it wasn't like that a few years ago.