Becoming a Writer

I would love to be a writer. I have stories crawl through my head all the time. I have pictures in my head and I can here how the characters sound. I just can't get it to sound right when I try to write. It sounds flat and my descriptions don't do what's in my head justice.
I have always had an active imagination. I first remember making up stories and characters when I was in first grade. I would finish my work and apparently I would disturb others so my teacher had me go to the closet. I created the greatest stories ever in there. Ever since then I have had stories in my system. I have tried many times to write them down but they just don't happen on paper. I won't be able to write about vampires or wizards or cow dogs and such. Those aren't things that I can relate to or want to write about.
I wish I could take video tape of my brain so that I could replay it and write the stories that are in there down. I would love to finally get it right and that means taking a chance again. Maybe I will. Who knows.