How do you get the raven and deep rothe forms , they were not listed when i got moon druid sub. I am lvl 3, so maybe they come on line at lvl 4?

Possibly. Let us know if they do when you level up!

Dire Raven is Circle of Moon, at level 4. Deep Rothe is level 4 druid.

IF they use the 5e rules flying forms are not available to level 8 for either type of druid

They don't. Dire Raven is available at level 4 for Circle of Moon.

This might be for testing purposes. They could change it to all druids, level 8 once the game actually has a level 8!

Level 4 should give swimming, but since the game don't have swimming, I can't see that happening. Could add a token crocodile though. Technically, the polar bear has a swim speed and CR 2, so shouldn't be available until level 6, but the BG3 version is weaker than the PnP version.

As per PnP, land druids should get level 2 moon druid forms at level 8. Moon druids should get tougher forms at levels 6 and 9.

It's definitely likely it is only for testing purposes, but also likely just for gameplay reasons, as there are a lot of opportunities to exploit verticality in the first act, far before level 8. Land Druids could follow the typical PHB rules, getting flight forms later, whereas moon gets forms earlier, and perhaps with scaling.