Unlike most disapproving parents of adults, I don't think LW's parents are in the wrong here. It is reasonable to ask your child to wait before making a major life decision, their idea of waiting was sensible and within cultural norms, and from LW's own description it doesn't sound like they're actually exerting undue pressure at this end of things. They're just unhappy.

Well, the truth is that sometimes our decisions are not going to make our loved ones happy. The only thing to do is to accept that.

Now, if LW is concerned that she's somehow not meeting her obligation as a Catholic to honor her parents then she should bring that up with a priest before taking further steps on this path. I think, though, that she's acted in good faith for these past four years, even going on a few trial dates, and everything ought to be clear in her conscience.