legolas is... what age?

[gilraën]

I found this in The Treason of Isengard

This is probably the point at which my father determined on the change of Galdor to Legolas. Legolas Greenleaf the keen-eyed thus reappears after many years from the old tale of The fall of Gondolin; he was of the House of the Tree in Gondolin, of which Galdor was the lord.