I was diagnosis with placenta previa after some spotting. i'm 15 weeks and still spotting-light brown. is this normal? if this will correct when?

Placenta previa: I'm not sure of your question - is placenta previa normal - NO. Is bleeding with previa normal - yes. Spotting just light brown sounds like either old blood or very slow bleed, which is better than brisk, bright red bleeding. Some previas "correct" themselves - that is the placenta moves away from the cervix area. This can happen at any time during the pregnancy.It has to be followed VERY CLOSELY!