I did the exact same schedule with vicinihil above, but I'm going to disagree slightly. Both first and last offer advantages - if you do it early, the bar is set lower and the opportunity to look good/rock the shelf is pretty good provided you're enthusiastic, polite, know your patients, and work your tail off. As the year goes on, yes, you will know far more and be better prepared for the rotation, but most attendings are keenly aware of where we are in our training. It's been my experience that their expectations are based largely on where we are in third year. In addition, you may know more of what's tested on the shelf, but so will everyone else, so it gets progessively more difficult to do awesome on shelves (and, by consequence, get awesome grades).
If you can't decide whether to do internal first or last you could possibly decide the schedule based on the timing of the other rotations in those pre-made schedules. For example, I did surgery first with vicinihil because I had zero desire to be a surgeon, and it worked out beautifully being done with that dreaded rotation so early in the year. Some people chose blocks because it allowed them more flexibility to be free during certain times of the year. Etc.
Bottom line: You're not screwed either way.