yeah man. just did all this.

You have to be in the reserves/guard first, i.e. swear in, then wait in line at the MPF for 7 hours just to get an ID card that looks exactly like the one you just had and update your info in DEERS...then you can sign up online. The good part, if I remember it correctly is: it can be retroactive for 60 days once you sign up, so you don't technically go without health coverage until you can swear in. So if your kid gets sick before all the paperwork is done, you aren't screwed.