Other then being level 20, what exactly is ascention?

What does ascention entail? Other then just being level 20...

its kind of like an "enlightment" i guess u could say from the RP standpoint of the game, no matter what lvl you are , you become 20 after you complete the trials.

You gain access to the last part of the ice continent which has most of the elite skill mobs in the game. Also the last armor crafters are on that continent.

i havnt read anything about the trials... is that just all the missions? if so, if i just do mission after mission, ill be 20 on the last one?

Level 20 =/= Ascension. It happens after you Ascend, certainly, but it is entirely possible and not unheard of to reach level 20 well before you Ascend. The actual act only exists for plot related purposes.. it means that, as a Chosen, your character has reached their potential by gaining the True Sight - that is to say, the ability to see (and to combat) the White Mantle's Unseen Gods ... the Mursaat.