"Who's to say that 'I feel charming/Oh so charming/It's alarming how charming I feel' is outside the range of a pretty working class Puerto Rican girl living in the West '60s in 1957?"
A girl freshly arrived from Puerto Rico wouldn't use flowery terms like "charming" and "alarming." If anything her English would be broken. I find it amusing that Maria speaks such perfect English. Take away the accent and she might as well be a typical American girl. My older sister, who was 15 when we came to this country (around Maria's age), still has trouble understanding the English language. She knows enough to get by, but vocabulary words and idioms are her downfall. Heck, she has trouble following English-speaking movies and is always asking us what is going on. Also, she's surrounded by Spanish-speakers (as Maria would naturally be). She married into a Puerto Rican family and their specialty is Spanglish, with the emphasis on Spanish.
Anyhoo, "I feel charming / Oh so charming / It's alarming how charming I feel" might be typical of a pretty American girl in the 1950s, but not a Puerto Rican girl who's only been in the US one month and grew up speaking Spanish.
Salve, Regina, Mater misericordiae
Vita, dulcedo, et spes nostra
Salve, Salve Regina
Ad te clamamus exsules filii Eva
Ad te suspiramus, gementes et flentes
O clemens O pia