Moles are extremely common. Many people are born with a few moles and develop others during their lives.
While it's important to look for signs of asymmetry in your moles or to carefully monitor moles which appear after the age of 20, most moles are actually benign.
Some warning signs that a mole may not be benign are changes in color or shape, itchiness or bleeding. It is crucial to be on the lookout for raggedy, blurred or frayed looking edges.
There are different types of moles. Congenital moles are present at birth and in fact have been confused with "birth marks."
Every one person out of one hundred, give or take, is born with congenital moles. The Cleveland clinic warns to watch if a congenital mole grows larger than 8 inches in diameter because they have a higher possibility of becoming cancerous later in life.
https://www.empowher.com/moles/content/what-are-moles