  Aging, the dependence of the dynamics of a physical process on the time $t_a$
since its original preparation, is observed in systems ranging from the motion
of charge carriers in amorphous semiconductors over the blinking dynamics of
quantum dots to the tracer dispersion in living biological cells. Here we study
the effects of aging on one of the most fundamental properties of a stochastic
process, the first passage dynamics. We find that for an aging continuous time
random walk process the scaling exponent of the density of first passage times
changes twice as the aging progresses and reveals an intermediate scaling
regime. The first passage dynamics depends on $t_a$ differently for
intermediate and strong aging. Similar crossovers are obtained for the first
passage dynamics for a confined and driven particle. Comparison to the motion
of an aged particle in the quenched trap model with a bias shows excellent
agreement with our analytical findings. Our results demonstrate how first
passage measurements can be used to unravel the age $t_a$ of a physical system.
