Well, I want to learn game development, I've already know a little bit about xna, ogre and DX but, I want to choose one of them and stick with it. I'm not trying to make a "directx vs xna, ogre vs opengl, etc." thread. Some people told me that it's better to learn an engine like Ogre because you can develop games directly and you don't have to worry about the low level details, I know that. Other people told me that it's better to learn a low level api before learning something like Ogre because you will able to understand how it works. Is it valuable to have experience with Ogre or another engine but don't know anything about a low level api? What do you recommend me?

Thanks in advance.