I'm glad to see you thinking about the AOS process now instead of waiting until after you guys get married here - It's good to prepare ahead for sure. I will say this though, right at this moment, I would devote your energies preparing for the interview. Make sure you have the I-134 ready, the proof of relationship evidence to bring as well as the civil documents needed. Once you get verbally approved for the visa and while waiting for it to be issued, then I would start to get ready for the AOS. At least that's the way Jaycel and I did it and we seem to be on a good path. We got her SSN issued, got married and filed the AOS all within about 80 days from when she arrived. We got her EAD approved 51 days from when we applied - So far so good