Our T12RBST fits "rather precisely" in our garage.
Things to consider: The edge of your garage door is usually a foot or two narrower than the garage itself, while you might have the total width to "fit" your camper and SUV, remember that you still want/ need to be able to get access to the sides of the trailer. In addition, if you want to actually open the A frame inside the garage, be aware of where your garage door opener motor and rails sit and whether you have the width and height for the trailer peak. When in position and open, the side of ours clears the garage door opener motor by less than 3 inches.
Length-wise, the spare tire on ours protrudes more than the bumper. When we park it, we have to drop it off the TV, and jockey it so that its perfectly square to the back wall of the garage, then lower the nose of the trailer some so that the rear bumper better hugs the wall. At that point, except for one bracket on the garage door we have an inch from trailer tongue to the garage door- when that bracket passes the tongue, I just press out on the door a bit until it clears...
It is a bit of a pain to get the trailer so precisely located, but definitely worth it to have it stored indoors, so add me to the folks encouraging you to measure twice, and don't forget the height of the peak should you want to open it up ( I keep mine open and vented )