How old was  Rose Hartwick Thorpe when she published the poem she is remembered largely for? 
Curfew Must Not Ring Tonight:  It was written when she was 16 years old and first published in "Detroit Commercial Advertiser". Rose Hartwick Thorpe: Rose Hartwick Thorpe (July 18, 1850 – July 19, 1939) was an American poet and writer, remembered largely for the narrative poem, "Curfew Must Not Ring Tonight" (1867), which gained national popularity.
16 years old