Need help- dying my hair situation.?

Well, if your hair is the "dull grey-ish" color right now and you want to go for a lighter brown, it should work! But since your brown is darker, it may turn out a shade or two darker than the box or hairdresser (however you're getting it done) says. But, it all depends on the brand of dye, color, tones, yadda-yadda. :)