Warning: Newbie with lots of questions

[Huggyd]

I just went out with the wife and pick up a new bike for her at Canadian Tire (C.T.) (local department store) She found one that she liked and she is happy with it.  I still have to psi the tires and lube up everything, I was wondering if there is anything else I should be looking at or making adjustment too (gearing, brakes, etc)??
Also I have looking at buying a bike for myself and while at C.T. I saw one called Supercycle, I have never heard of this brand before and was hoping to get the low-down one it? (is it good or bad, can you get parts for them) I have been out of cycling world for a while so I don't really know a lot so sorry about the questions but also I see bikes with one disc brake on the front and a rim brake on the back or some do it the other way around, does this matter? does the size of tires (24" 26" 27.5") make a difference other then the height of the rider. For the most part I am not about to do any downhill mountain events but I am looking at doing some rough trails in the woods so I am looking for something that will handle that.
Any info or insight would help.

[John Nelson]

If it feels good to ride, then it's the right bike. I think the best bet is to take a bike-knowledgeable friend with you when you go shopping. And take a nice long test ride.

As for your wife's bike, keep air in the tires and lube the chain. As long as it shifts and brakes well, don't adjust anything. If she's going to go very far from home, make sure she carries a phone and/or knows how to fix a flat.

If you're still riding after a couple of years, you'll be in a better position when you buy your next bike.