68c, will I be able to drop a packet for selection?

[Gage]

I am currently a Private, in AIT for 68c(liscensed practical nurse), My ultimate goal for my Army career is to be a 18D. However from what I've been reading my mos is apparently under strength. I won't be a specialist for two years from now anyway. But if my mos is still under strength at that time will I still be able to drop a packet for SF? I am only asking this so far in the future because it is possible for me to ask to be reliefed from the course and reclass.