Forum:First Age question

Well, here's a question about something that troubles me a lot and i can't figure it out exactly.

Is the First Age a sub-part of the Years of the Sun OR is spanned across the Years of the Trees and the Years of the Sun??

In the History of Arda is stated that the First Age begins with the awakening of the Elves at Cuivienen, which happened during the Years of the Trees.

On the other hand, in the Timeline of Arda is stated that the First Age begins with the awakening of Men at Hildorien, which happened at the very beginning of the Years of the Sun!

Does someone has a proper answer?...I'm a little confused with this, although i'm starting to feel that the second assumption is more logical, because all the Years (Lamps, Trees, Sun) lasted several ages (as stated in the "Timeline of Arda").