/played displays how long you have played this character for.
Input /played in the chat box, then you will find how much time you have played in the Path of Exile. In the following example, it shows I have played for 6 days, 13 hours, 38 minutes, and 50 seconds.
/age displays how long ago you created this character. In the following example, it shows that this character has created 50 days, 16 hours, 19 minutes, and 17 seconds.