Understanding Miiverse & Nintendo ID's?

The explanation, thus far, is not enough to help me understand just what happens for a person, like myself, who has yet to purchase a WiiU (it's in the budget for the 13th of this month), but is already updated to the Miiverse on their Nintendo3DS, which is asking for a Nintendo ID.

If I do not have a WiiU yet, and I choose an ID now, then what happens to all of my Wii e-shop points and purchases that I've made in the past, after I buy my WiiU and log in with the ID that I created prior to owning the WiiU? According to the instructions and awareness information, it reads as though I will lose that access and those points if I connect my 3DS without having a WiiU yet.

Can someone please explain the process better for me? I'm apprehensive, at this time, to create an ID on my 3DS for the Miiverse prior to my ownership of the WiiU. I've got plans to back up my Wii's purchased games from the eshop and transfer it to the WiiU, via the app they provide online. But... well... it's all just so very confusing at this time. I'd like NOT to accidentally block myself out of using my own points or accessing my purchased games.

Thanks for any clarity in this!!