Maybe it's just me, but if I was a young couple thinking of having kids in a few years, the last thing I would be doing is buying a brand new ~60k luxury SUV/CUV. The likelihood of you keeping it for 6+ years is low with so many life changes coming your way, and there are just many more practical ways of spending (saving) that kind of money.
Back on topic though, having a Q3, I wouldn't consider it big enough for a family of 4. Of course you could make it work (generations did with smaller vehicles), but it's pretty tiny with the back seats up. I keep mine down all the time for shuttling the dog around and it's fine, but coming from a Wrangler Unlimited I do find it SMALL. On the plus side it's an absolute blast to drive. I know people hate on CUV's, but I've owned plenty of different ones and just considered them as practical to have, but this is the first one that actually puts a smile on my face to drive. Put it in Sport and Dynamic modes and it growls and handles like crazy, it makes me wonder how nice it must be to drive a Macan.
As for the turbo discussion, this is my first time owning one, it's a 2015 and with ~50k I had the turbo fail/replaced this past summer. Luckily it was covered under warranty, would have been $2200, but it definitely solidified for me that this vehicle will be a "time to move on" once the warranty is ending!