Read the original question here.
This is a fantastic question that I have been thinking about myself! Our culture seems strangely obsessed with marriage, and sometimes this can have the devastating effect of making single people feel that being single is worthless, which could not be further from the truth.
To get the technicalities out of the way first: As far as a permanent calling to the single life, it seems to me that Church teaching suggests that such a calling would take the form of consecrated virginity, but like you I haven’t been able to find anything official either way (you might check out this article as an example of what people say unofficially).
Instead, I have heard trustworthy folk refer to a “temporary vocation to single life,” which is a good way of thinking about the state of being single while waiting for and discerning a permanent vocation to marriage, religious life, or consecrated virginity.
Some people talk about single life as though it is just a time to work on yourself so that you’ll be an awesome wife/nun/consecrated virgin in the future. It’s true that single life does give you this opportunity, but I think there’s more to it than that. Our God is a God of the present. He has a plan for each day of our lives, including each day we spend as a single person.