is senorita rosa Miss. or Mrs. or does it matter?

Senorita refers to an unmarried woman -- so it's "Miss".

Indeed it matters!

señor = Mr, abbreviation = Sr.
señorita = Miss, abbreviation = Srta.
señora = Mrs., abbreviation = Sra.

Sra!

To determine whether "Señorita Rosa" should be referred to as Miss or Mrs, it is important to consider the cultural norms and customs associated with the use of honorifics in different languages.

In Spanish, the term "Señorita" typically translates to "Miss" and is used when referring to an unmarried woman. On the other hand, "Señora" (abbreviated as "Sra.") is the equivalent of "Mrs" and is used when addressing a married or older woman.

However, it's crucial to note that preferences can vary, and some individuals may have personal preferences regarding how they would like to be addressed. Therefore, the best approach is to politely ask Rosa how she prefers to be addressed, as she knows her own preference best.

If you're unsure about the cultural norms or individual preferences, it's always respectful to use "Señorita" as a default term until otherwise specified.