I've been told i have good genetics what does that mean ?

Means you are lucky: To have good genes mean you do not have any familial disease in your family.You have inherited a pretty good body as a whole.And now it is up to you to use these genes in a constructive way and if you do the right things and stay away from smoking,drugs,have healthy eating habits,avoid obesity,exercise regularly and get regular check ups,then you will live a rather long and healthy life