I've read the wiki about this and it states : "Unenchanted Daedric weapons will begin to appear throughout the world at level 46 and enchanted weapons can be found at level 47, albeit very rarely."

However when I first entered the, what's it called... "Alduins wall" or something, you know where you go with Esbern and enter the old blades hideout.

I found a Daedric sword there in the large chest when entering the place. I was probably around 33-35 then. I found a deadric one handed sword.

is this a bug or intended or was I just very lucky due to random leveled loot?

Are you sure? The sword I found in a chest was an Akaviri blades katana style sword, Dragonbane. That's not daedric.

I'm level 40 and have not found a single piece of daedric weaponry or armor yet - other than a low number of daedric arrows dropping in dwemer ruins of all places. But even that has been a rare event - I have only 22 of them so far.