In informal English, 'for ages' simply means 'for a long time'. If you say to your friend 'I'm just going to buy a drink', and then you disappear for 15 minutes, when you return, your friend might say 'You were gone for ages. What took you so long?' In other situation 'ages' can mean several days, or several months. It isn't necessarily 'years'. It just means 'a long time'.