You have to remember that once you get in you will be doing basic, so you can‘t do anything else then. You will move on to your Bat. school or Trade school, driving school (depending on trade) etc. Once you have left all that behind and get posted to your home unit you may have a chance to go to school, granted there is a school offering the course you want in your area, but, if you have to deploy to the feild or an Operation, you are going to miss all those classes.
I have a friend in Kingston that has tried three times now to complete a night course at Queens. Every time he tries he gets sent somewhere making it impossible to finish his work.
Chooses one or the other. Or join the reserves and do your plumbing course.
I am in the same boat as ^ as I am going to be going to school for two years (payed for by the Army) but I will be a Civi pretty much, untill I am done.