User blog comment:Drakan95/Dante Alighieri vs The 7 Deadly Sins. Epic Rap Battles: Cartoons vs History. Bonus Battle/@comment-5412428-20160114020009/@comment-25519319-20160114182547

Well, like I said...don't blame me. xP

Also, even Wikipedia states this:

The poem begins on the night before Good Friday in the year 1300, "halfway along our life's path" (Nel mezzo del cammin di nostra vita). Dante is thirty-five years old, half of the biblical lifespan of 70 (Psalms 89:10, Vulgate), lost in a dark wood (understood as sin).

And since Dante was borned somewhere 1265 the calculation should be simple: 1300-1265 = 35.