For what it's worth, what I saw as a student and later an instructor at military basic flying training units (FW and RW) in Aus indicated that students with previous flying experience would generally go pretty well through the early stages, as you would expect, but would quickly come back to the pack when the intensive things they hadn't done before (e.g. formation, time on target low nav) came up.
Sometimes the 'military way' (e.g. for fixed wing, elevator for aim point and power for airspeed on final rather than the apparently well-used civvy way of attitude for airspeed, power to adjust the aim point) would mean people had to forget previously learnt habits and start using new ones, a difficult task in some cases.
As a general rule, I'd say if your civil flying has a sound attitude flying basis (i.e. set power and attitude, balance, trim (if applicable) and get into and maintain an effective scan) then well and good, but if not, you may have a bit of work to do developing same.
To cut a long story short, if you want to continue flying, do it (as Crab says), but more hours won't necessarily be of much benefit on a military pilot course. Probably not a bad thing to do a few rotary hours to get the taste of why that fixed wing mob are always jealous of their more advanced rotary brethren, but don't feel like you have to get a licence to boost your chances in the forces.
Good luck!