Bummer you have to wait, but it sounds pretty standard.
I must say I don't understand the rationale, though. It's likely the blood work simply says "go" or "no go" on a standard regimen. For the majority of cases, they just verify that their plan is ok and then start it. That shouldn't need a follow-up. If something unusual happens, then you follow up. It sounds to me like an excuse to book another appointment, coupled with some old fashioned gatekeeper philosophy. (Even if they're not actively gatekeeping.)
But... Tori's right. It's 3 weeks out of the next forever, so you'll get there before you know it. And after all, the best part of Christmas is the anticipation, right?