Question: How old was  Rose Hartwick Thorpe when she published the poem she is remembered largely for? 
Context: James Colnett (1753 – 1 September 1806) was an officer of the British Royal Navy, an explorer, and a maritime fur trader.  He served under James Cook during Cook's second voyage of exploration.  Later he led two private trading expeditions that involved collecting sea otter pelts in the Pacific Northwest of North America and selling them in Canton, China, where the British East India Company maintained a trading post.  Wintering in the recently discovered Hawaiian Islands was a key component of the new trade system.  Colnett is remembered largely for his involvement in the Nootka Crisis of 1789—initially a dispute between British traders and the Spanish Navy over the use of Nootka Sound on Vancouver Island that became an international crisis that led Britain and Spain to the brink of war before being peacefully resolved through diplomacy and the signing of the Nootka Conventions. Gilbert Francis Lani Damian Kauhi (October 17, 1937 – May 3, 2004), also known by the stage names Zulu and Zoulou, was an American actor and comedian.  He is remembered largely for his portrayal of "Kono Kalakaua" on the long-running television program "Hawaii Five-O". Curfew Must Not Ring Tonight is a narrative poem by Rose Hartwick Thorpe, written in 1867 and set in the 17th century.  It was written when she was 16 years old and first published in "Detroit Commercial Advertiser". Mary Muthoni Nyanjiru (died March 16, 1922) was a Kenyan political activist remembered largely for the manner of her death. Adeline E. Knapp (March 14, 1860 – c. June 1909) was an American journalist, author, social activist, environmentalist and educator, who is today remembered largely for her tempestuous lesbian relationship with Charlotte Perkins Gilman.  In her lifetime, Knapp was known as a fixture of the turn-of-the-century San Francisco Bay Area literary scene.  An outspoken writer who often addressed controversial topics in her columns for the "San Francisco Call", Knapp wrote on a wide range of subjects from livestock to the Annexation of Hawaii.  Though often drawn to progressive causes like child labor and conservation, Knapp also tended to espouse reactionary views, as evidenced by her anti-Chinese sentiments and criticisms of the women's suffrage movement.  At a time when many American women were joining the movement to extend political and voting rights to women, Knapp spoke in state senate hearings in New York expressing doubts about the benefits of suffrage to women, and she allowed her speeches and letters on the topic to be used as propaganda by the anti-suffragism movement.  Knapp was also the author of numerous short stories, as well as a novel set in the Arizona desert—works reflecting her outdoor enthusiast sensibilities, keen intellect, and interest in Western regionalism.  These works, though praised in her lifetime, today have few readers among enthusiasts of Western fiction. Carl Wilhelm Friedrich Oesterley (22 June 1805 – 29 March 1891) was a German painter and art historian.  He is remembered largely for creating oil paintings with Biblical themes. Norman Demuth (15 July 1898 – 21 April 1968) was an English composer and musicologist, currently remembered largely for his biographies of French composers. 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.  Other poems followed, among them being "The Station Agent's Story," "Red Cross," and "In a Mining Town."  Although a busy and prolific author, she was ill for some years.  In 1888, she and her family removed to San Diego, California, living in Rosemere, Pacific Beach. Johann Samuel König (July 31, 1712 in Büdingen – August 21, 1757 in Zuilenstein near Amerongen) was a mathematician.  Johann Bernoulli instructed both König and Pierre Louis Maupertuis as pupils during the same period.  König is remembered largely for his disagreements with Leonhard Euler, concerning the principle of least action.  He is also remembered as a tutor to Émilie du Châtelet, one of the few female physicists of the 18th century. Thomas Ford (December 5, 1800 – November 3, 1850) was the eighth Governor of Illinois, and served in this capacity from 1842 to 1846.  A Democrat, he is remembered largely for his involvement in the death of Joseph Smith, and the subsequent Illinois Mormon War.  He is also the author of "A History of Illinois" (Chicago, 1854), published posthumously about the state from its founding in 1818 until 1847.
Answer: 16 years old