I am 16 years old.I have started bleeding 4 days prior to my period. I haven't been on any form of birth control. My last period was on September 14,2006. It is a light color and it is not a heavy flow. I have been bleeding for 1 1/2 days. It is not getting any darker or heavier. Could this be implantation bleeding?

Please read this thread about implantation bleeding.

You leave out a lot of information here... such as your age

Are you or have you been on any form of birth control.

The more info you give the better we can help you. Your question is really too vague.