I don't think you did any damage with this discussion, so best to get that out of your mind. Feeling like you upset her will only keep you from bringing up other issues in the future, and you don't want a relationship like that. It's called having to walk on eggshells - not good for anybody.
She got upset because she's created some sort of pressure around this act that I'm not even sure she understands. To you, me and many many other people here, we don't get what the big deal is about it. To a few others, they empathize with her - yet (barring some sort of trauma associated with oral sex) they can't quite verbalize their distaste of it, either. Most people like this (men, included) simply decide at some point that it's "gross" or "disgusting" or it's something only hookers or people with loose morals do. Or, as I suggested earlier, it's only for sexual relationships or encounters with people who you are not going to spend the rest of your life with - because those people should expect better of you, or themselves.
The reality is, and I'm loathe to agree with this, trust me, is that many women have a pre- and a post-marriage persona. As much as many men like to think it's specifically in order to "land" a man, I disagree (though that DOES happen). I truly believe that many women utilize the time of their lives before marriage in a much different way than post-marriage. That it's 'okay' to be this way or that, or to do certain things, with certain people.
While no woman truly desires to feel used, I think something clicks in them once they meet the "right" man, and they somehow expect better of them. Like, he's worthy of marriage, of being a father to my kids, of growing old with. Things like BJ's and such are above them. Suddenly, 'being used' is an issue. Where previously one could own something like giving a guy a BJ, now it's "the past" and "I don't do that sort of thing any more", "those guys meant nothing, so I didn't care".
BJ's stopped for me once my wife and I started getting more serious. Prior to that, it was a non-issue. They happened occasionally, sometimes for no reason at all. A few times in the car, while driving, even. I never expected one, was never demanding of it, never once said something like "hey, it's been a while...". And I took care of her in that way, too.
Then it stopped. Right around the time we discussed moving in together. Years later, I find out she "hates" it. But it's something she'd always done, including with me. And when I straight up asked her, if I were to die tomorrow and she started dating again at some point, would the next guy literally never get a BJ? She had no answer. And that's because she would. Until things get serious again.
And that's what I see time and time again with this topic - women stop giving them at some point. Not because their husband/serious boyfriend isn't worthy of them - but because it's somehow associated with casual, non-serious relationships. Ironically, because the guy is a 'keeper' and is too good for such a low-standard standalone sexual act.
Obviously there are many women who enjoy giving oral sex, and/or don't view it as a degrading or disgusting act with their partners, including husbands. But for many, there's a negative stigma attached to BJ's. And it's honestly a shame that so many feel this pressure and anxiety from such a simple thing.