Had an echocardiogram that showed "mild mitral regurgitation" should I be concerned?

Mild mitral regurgit. No need to worry about mild mitral regurgitation. It need follow-up echo in 1 year, and if stable need follow-up after 3-5 years.
Talk to cardiologist. Your cardiologist can determine whether or not you should be concerned depending the severity of the regurgitation. Many people have a mild cardiac valve abnormality, but your cardiologist will know more specifically how concerning it may be.
Mild mitral regurgit. Mild mitral regurgitation is usually a mild problem. It can progress in time to a more signficant problem but usually does not. Attention to healthy life practices is prudent and follow up to see that the mitral regurgitation doesn't get worse are prudent steps.