So ARes is not the same as regular reserves (army or navy). Air Reserves is more of a full time job, with all your courses being full time, and taskings are also full time.
Army reserves is part time (one night a week, one weekend a month) with potential for full time contracts. If you were joining the army as MSE Op (which makes way more sense to me for some reason), I would just say learn the difference between being sore and being broken. The training is hard on the body, and going camping with the CAF is very different than going camping on your own (even if you are used to roughing it).
You will be sore after every training weekend for the first little while, but it should improve. We had one guy who joined reserves when he was 55, and showed up at the MIR after the first weekend of BMQ claiming he got injured on BMQ. After an assessment, turns out he was just not used to the amount of physical labour they did that weekend, and sleeping on a cot was hard on his body. He wasn't broken, just sore. He couldn't seem to understand the difference.