Eternal Membership question

[andaxiamoonstar.livejournal.com]

I am hoping I can afford to get an Eternal Membership this year, but I am not sure yet if I can.  Therefore, I was wondering if I went ahead and pre-registered at the current rate, would that amount be counted toward the $750 of the Eternal if I can purchase that after all?  Or would I have to pay the full $750 even after pre-registering?  I need to know because I would like to get my registration in ASAP, but don't want to pay more than I need to if the Eternal Membership works out.

Thanks!