Navy important question about choosing a rate?

Ok I go to MEPS Monday to get my rate, I would've got my job back on Feb 1 but there was none open and the one aviation job that was open I couldn’t take because I fail the depth perception test. I took the test again and pasted it, my recruiter send the papers up for review and we are waiting to hear back about the waiver. Therefore he told me that I that when I go to MEPS Monday take a job that I kind of like or any job and once the wavier gets back I could change me rate while I'm in DEP, is this true? He also keeps talking about some air pack crewman rate or something like that, whets that job like? Please give me some good info because Monday will be here very soon