Can it be possible for you to get a birth mark in your 30's?

Word definitions: Many people use terms in varying ways and the choice of definition varies with the observer. I consider birth marks to be present at birth or within the first month or so for some that pop up from just under the skin. Any skin mark that arises in a 30 year old would never fit my definition. Most would consider it either a benign or not so benign nevus, depending on specific appearance.