Constant excess vaginal mucus?

So I've read all the other boards about this problem but they all seem to be a bit different.. Here's my situation: Around six months before getting my first period I began to get discharge every day. It's consistency was a lot like that of mucus from your nose and was a very light greenish color. Ever since then, about a year and a half, I've been getting discharge every day, including the days of my period. I get all the different types, watery and clear, like mucus from your nose, and sometimes brownish (most times after my period). I feel like my situation is abut different from others seeing as I get it constantly and people say it's normal to get it occasionally. I know I don't have an infection because there's no burning or itching and it's been going on for two years now. I've asked my doctor but all she's said is that it's because I'm young. But my question: is it normal to be going on this long, even though I am young (sixteen now, 14 when I got my first period)? And is there a way I can help it? All of my underpants get ruined overtime and I live in constant embarrassment that someone may find out.