I imagine that by the time Lucent leaves Sharlayan (shortly after Endwalker) he's a full sage, and that the process of becoming a sage takes approximately as long as becoming a doctor IRL. so, he's been living there like thirteen years, give or take a few? and he came to Sharlayan as an adult after living some indeterminate number of years as a Wood-Warder
...so, how old is he? I have no fucking clue, and neither does he
(fallen london stamps by