Does A Painless Mole On The Leg Need Medical Attention?

Hi ,i have a mole approx 3cm round on my left lower calf,it does not itch,its not aggressive and has been there for years,its only a customer of mine who is a nurse keeps telling me to get it checked out for peace of mind!! i teach circuit training etc,so she can see my legs!! in case it matters i am 56yrs old and run and cyle a lot outside,thanks in anticipation of your advise.Ray Handley.