Try updating your user id in your .json file. from your .json file: "html": "FFRPG_3e.html",
"css": "FFRPG_3e.css",
"authors": "Kiyomi Nakamura (Kiyomi N. on Roll20.net)",
"roll20userid": "11152 3 ",
"preview": "FFRPG_3e.png", but from your profile, the last digit of your user id is missing (/users/1115237/kiyomi-n). Hopefully changing that (and waiting for it to propagate) will grant the Achievement. Otherwise you'll probably need to make a post in the bug report forum. Also (though I don't know why), I don't see the preview picture show up for the sheet on the dropdown; it shows a broken image for me for both firefox and chrome. I can see the image on GitHub just fine, however. Nice looking sheet. :)