age difference

:  the time of life at which some particular qualification, power, or capacity arises or rests

:  majority

:  one of the stages of life

:  to become old :  show the effects or the characteristics of increasing age

:  to acquire a desirable quality (such as mellowness or ripeness) by standing undisturbed for some time

:  to cause to become old

:  the quality or state of being dissimilar or different

:  an instance of being unlike or distinct in nature, form, or quality

:  a characteristic that distinguishes one from another or from the average

:  differentiate, distinguish