The naaru are the creatures of the light, A'dal.. Xi'ri.. etc.
They aren't gods, they are mortal beings.. but wise above your imagination.
As Khadgar says in Shattrat "I've learned more from A'dal in half a year, then all the years in the Stormwind Library" (or so)
The Draenei, like humans, worship the light, but like elves.. also show great admiration for the Earth and nature.
The light is the power of will and faith, not a physical god or so.. more like a power that is all around us and that can be called upon by prayer, faith, willpower or even abuse (like the bloodknights enslave naaru to use their powers of the light for themselves)
The Draenei have the greatest respect for Naaru from all races, cause the Naaru saved them from being wiped out by the burning legion.. their race owes a lot to them, they do not worship them like gods tough.. but as the greatest form of respect and wisdom.
And Argus is the homeplanet the draenei were originally from, it's somewhere across the cosmos (if Sargeras didn't destroy it)
BTW.. I saw you were asking about age, my guess is they are like nightelves.. becoming REALLY old. As they are still little after almost being wiped out of the galaxy several times. + Velen still lives, he is ofcourse an exception but still.. the draenei traveled across the cosmos for thousands of years and Velen still lives. So probly even older then elves? :O
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Short Draenei lore explanation:The Draenei were once a race known as the eredar, on their homeworld Argus.. led by their 3 leaders.
Sargeras had started his destruction of the cosmos already and his burning legion had his eyes on Argus.
2 of the Eredar leaders gave in to Sargeras, becoming their loyal servants and got corrupted.. on wich Sargeras made them powerfull beings
The 3th was Velen, the current leader of the Draenei.. he had a vision and saw that this would only lead to destruction, so he prayed and tried to guide his people to the right path, not joining the burning legion.
His prayers got overheard, the Naaru came from across the dark beyond (space) and with their help Velen led his people to safety.. on wich they renamed their group of survivors to Draeni meaning: "the exiled ones"
The Naaru explained that there were other powers in the cosmos like them, with the goal of stopping the burning legion.. to one day form an army of the light against the burning legion. The Naaru helped them escape on the edge, Velen and the draenei became nomads and traveled across many worlds.. being chased by the Burning legion for thousands of years.
Then after a long time they found a peacefull planet, wich they settled on and called Draenei "Exiles Refugee".
This was the homeworld of the orcs, the draenei and orcs lived peacefully besides eachother.. leaving eachother alone and having only limited trade. Until Kil'jaeden discovered their planet.
Corrupted by Kil'jaeden and the burning legion, the orcs and draenei engaged in a war for about 8 years.. 80% of the draenei got killed, since they were no match to the felcorrupted orcs. After the war many more draenei got heavily affected by the orc warlocks fel energies.. causing many more to mutate into lesser forms (the broken and lost ones).
The world of Draenor was eventually torn apart and is now known as Outland.. The draenei fled to Azeroth, with the Exodar mainly.
(Handy link about the Draenei lore, where I got most of this from:
http://www.wow-europe.com/en/burningcrusade/townhall/draenei.html)-------------------------
I hope that helps you out a bit
GL Rping