It's never too late. I have an intern under me this summer who's in his 50's, retired and went back to school to do something he was always interested in.

The UX/UI vs. architecture question is sometime only you can answer. Do you want to design app/website interfaces or are you interested in the design of the built environment and also the process (construction) that facilitates it.

As far as career prospects, now is a horrible time to be coming out of architecture school but the 5-6 years before now have been the best time in history to start out doing this. Firms couldn't hire enough staff to do all the work they had coming in. I really believe this is a hiccup that the industry will bounce back from in a year or so. Starting salaries still aren't as high as in some other fields but it's not unheard of to clear mid 50s your first year out. The last AIA salary report put the average salary for all registered architects in the US at like 93k. At my office of ~200 architects and interior designers, I would estimate that 50-60 percent of the licensed architects make 6 figures. My point in telling you all of this isn't that it's an easy, comfortable career but that all the doom and gloom you'll read on reddit and archinect isn't the reality for everyone doing this for a living.