Agnes was born in 1759. She passed away in 1841.
"Agnes Maclehose (26 April 1758 – 23 October 1841), or Agnes Craig, known to her friends as 'Nancy' and to Robert Burns followers as Clarinda, was a Scotswoman who had an unconsummated affair with Burns during 1787-88, on which he based the song, "Ae Fond Kiss" (1791). The pseudonyms of her 'Clarinda' to his 'Sylvander' were adopted by the pair for confidential correspondence purposes.
Agnes was born in Glasgow, the third of four daughters of a prominent surgeon, Andrew Craig. Her mother was Christian Maclaurin or McLaurin (d. 1767), daughter of John Maclaurin, a minister of the Scottish church. Her sisters were Margaret (b. 27 January 1752), Lilias (b. 25 July 1754), and Mary (b. 11 May 1764).[2]
https://books.google.co.uk/books?id=RH5CAAAAcAAJ The correspondence between Burns and Clarinda: With a memoir of Mrs. M - gives info on her life and social circle.
http://www.robertburns.org/encyclopedia/MLehoseAgnesCraigClarinda1759-1841.555.shtml
https://en.wikisource.org/wiki/Maclehose,_Agnes_(DNB00)
http://www.readallday.org/blog/robert-burns-and-the-clarinda-letters/
https://en.wikipedia.org/wiki/Ae_Fond_Kiss