Time to command is roughly 2 years from joining. You need two good sim checks (1 year) andthen be nominated. From being nominated to getting out on the line it seems to be about a year.
There's a back log of about 80 people waiting for commands at the moment.
BFS is pretty easy to get as not many people want to live there. Over time it will fill up and then become "dead mans shoes". At the moment though chances of getting a command there are pretty good.
Direct entry command is unlikely unless you've something the management can't do without.
However a year is a long time in eJ and you may be propelled into command quicker!