While we later found out about the moral ambiguity of the Force in the later books of the EU, the initial concept was there's a Light Side and a Dark Side, so it makes sense that the Jedi Order would start out that way.
Yes and no. They treated it in far too simplistic terms which I felt undermined the basic concepts at play.
You act too aggressively or get angry too much? You're exiled to the lightside moon until you calm down. You act with too much compassion and passivity? Got to the dark side moon and learn to kick puppies until you're in balance. They treated it like the kind of polar point based morality scale you get in RPGs. Which is fine for game mechanics, but that's not how a philosophy works and was overly literal in it's interpretation of the concept the force.
Again though, even if we put that aside, they never even showed how or why they came to this idea. It was just there, fully formed.
It would have been more interesting to show the Jedi begin as monks and missionaries, even apostates under the decaying rule of the Rakatta. When I think of the very early Jedi, I picture something more along the lines of the the ancient Mystics from 'The Dark Crystal'. Truly spiritual practitioners.
If it were up to me I'd cast them as functioning much like the church did in medieval Europe, at least in the sense that it was an organisation that spanned many kingdoms and for the most part, was the only common point many of them shared.
In the beginning the Jedi would be missionaries and educators who preserved knowledge in the ruins of a fractured empire, having temples and missions spread all across the galaxy. Later ubiquity and neutrality would make them natural mediators and envoys who were trusted by all parties to settle disputes and convey messages without distortion or prejudice. Passive almost to a fault until at some point they began turning their martial skills towards the physical defence of the weak and helpless, but always and only as a last resort.
That's how I see the origin of the Jedi, not a bunch of upstart apprentices that are eager to jump into a war so they can test out their newly forged lightsabers. That sounds more like the origin of the Sith, much later down the line.