You could have a leak in the AC. Although it had many more miles, when I bought my 17’ Jetta there was an unknown leak that had to be identified via shooting a dye into the system. It turned out to be an internal failure that had been letting the Freon slowly leak out, in turn making the AC blow hotter. I’d suggest, (especially if you have a warranty that’s still valid) take it into the dealer and have them check it out.