Birthmark: cause for concern?

[asking_for_help]

(20 years old) I have had a birthmark on my back for my entire life. It has always been the same light brown color all the way through, with no color in between. But, recently, a tiny dark brown dot has appeared around the edge. It is a symmetrical dot that almost appears like another mole. Should I be worried?

[CurfewX]

This doesn't sound concerning.  Moles of concern are generally larger than a pencil eraser head, with irregular borders.