Oral Sex Imbalance

Married for 18 months and my wife is averaging 2-3 blow jobs a year. When dating, she eluded that she was saving parts of our sex life for marriage. I go down on her nearly every time, which she definitely enjoys. I've mentioned how much I enjoy receiving, to which she responds that she's never been 'into that' and gets upset that I would ask.

I've stopped asking, but I can't help but resent her at times for it. Our marriage and sex life is otherwise happy making me feel petty for feeling this way, but I do. She can tell when I'm not happy, but I can't tell her why because it leads to an argument.

I don't want her to feel forced, but I feel like she's being as selfish as I probably sound right now. Am I making too much of nothing?