Well feel free to disregard what your girlfriend was told, and what everyone here has told you. Roll the dice and have her come back ASAP. If she isn't allowed in, it sounds like you can just go see her in Indonesia periodically before you retire in 18 months.
Or you could listen to everyone (including your gf), and hold off on her returning immediately. Go visit her sometime(s) in the next few months before she comes back here again to visit. 8 months, in the grand scheme of things, isn't that long.
Also, getting married in Indonesia is a lot more paperwork than here in the USA. Good luck!