A light-year measures distance
A light-year is about 9.46 trillion kilometers. It is a distance unit, not a duration, even though its name includes the word year.
Light-travel time lets astronomy reveal the past. For nearby educational examples, a star ten light-years away is seen by light that traveled for about ten years; cosmological distances need additional care because space expands.
Wonder about this
Would you measure your age in light-years?
A science clue
No. Age is time; a light-year measures distance.