Yes, it says she was 18. She died without receiving sacraments, her body was accompanied by the "colegio" (I think of them along the lines of the Knights of Columbus today), and she was buried for free as they were too poor.
Catholic sacramental records are only going to contain Catholic sacramental stuff. Once in a blue moon, you'll see something along the lines of "The following people all died in the earthquake of [date]." That's the exception. Generally, you don't get a cause of death until the Civil Registry records that happened much later. I've seen cause of death in the 1900s era. Not sure if I've seen any from the late 1800s.
Cheri Mello
Listowner, Azores-Gen
Researching: São Miguel island: Vila Franca, Ponta Garca, Ribeira Quente, Ribeira das Tainhas, Achada