Has there been a baseline established for your heart's diminsions. Your heart is pumping effectively and normally. Mild, trivial, trace, etc regarding valves is considered medically insignificant and almost always does not progress or cause a problem.
Depending on the underlying cause (usually high blood pressure) can there be an evaluation for any seriousness of the chamber sizes. Your mild valve insufficiency should not be the cause, and your chamber dimensions are estimates. Regardless, it isn't of any concern as expressed by your doctor, and a followup exam can be more definitive whether there is a treatable problem or not.
Thanks for sharing, and take care,