In context of the story, I assumed they put “lifelong Catholic” to contrast with her husband Bob, who the story mentions did not become a Catholic until 1996.
As for your question of, is anything rare about lifelong Catholics, did the story mention anything about it being rare?
If so, I missed that.
BTW, I’m not Catholic.
Wouldn’t want you to assume facts not in evidence...
“Steadfast” is the term I would have used.