Enjoy it. Take advantage of it. Use it.
A couple of weeks from now when you're looking anxiously at the calendar and back at your page count, concerned that you won't actually be able to do it this time, remember how you feel right now. Today and this week is the motivation you need to push through to the end of the month, and to push through to hit 100+ pages.
So while I urge you to hold on tight to the exciting motivation you're feeling this week, I ask you to do whatever you can to keep writing when the excitement begins to fade a bit. Remember how you feel right now, and know that when you hit 100 pages (and beyond), you will feel it again.
This is just the beginning of a crazy, fun, frightening adventure. And it's worth it to see it through to the end.