Then I think you've done all you can and should do. If she brings it up again, great. If not, maybe let it be. If someone feels the siren song of the ocean (or lake) calling them--like scuba is something they have long wanted to try--they're still going to pursue that calling even after a crappy DSD experience. To put it another way, if a crappy DSD experience is enough to deter someone, maybe it wasn't their thing in the first place. A private DSD might have been the way to go in the beginning, but you couldn't have known that. Even then, I am getting the feeling that diving never would have been her thing.I've already brought that [private DSD] up.
My first wife was a trouper and did the OW course with me, and we duly spent one day diving on the trip to Australia we had been planning. But she really did not like the amount of gear and preparation it took. It never would have become something she wanted to do again and again.