Question: What is the earliest year that Juliane von Schwellenberg could have served Queen Charlotte of Great Britain as the queen's bedchamber maiden?

Context articles: Queensbury, New York
Frances Newton, Baroness Cobham
Irish migration to Great Britain
Queen Charlotte Triple Junction
Charlotte of Mecklenburg-Strelitz
Jane Stanhope, Countess of Harrington
Samuel Wathen
Juliane von Schwellenberg
Queen Charlotte (1812 ship)
Hired armed cutter Queen Charlotte

Queensbury is a town in Warren County, New York, United States.
 The population was 27,901 at the 2010 census.
 It contains the county seat of Warren County, located at a municipal center complex on U.S. Route 9 south of the village of Lake George.
 It was moved to the complex in 1963 from the original county seat of Lake George.
 The town is located in the southeastern corner of the county and is part of the Glens Falls Metropolitan Statistical Area.
 It is named in honor of Queen Charlotte, the consort of George III of Great Britain and Ireland.
 Although primarily located north of the city of Glens Falls, Queensbury surrounds the city on three sides.
Frances Newton, Baroness Cobham (1539 – 17 October 1592) was an English aristocratic woman who served Queen Elizabeth I of England as a Lady of the Bedchamber, and was one of her closest female friends.
 She was the second wife of William Brooke, 10th Baron Cobham.
Irish migration to Great Britain has occurred from the earliest recorded history to the present.
 There has been a continuous movement of people between the islands of Ireland and Great Britain due to their proximity.
 This tide has ebbed and flowed in response to politics, economics and social conditions of both places.
 Ireland was a feudal Lordship of the Kings of England between 1171 and 1541; a Kingdom in personal union with the Kingdom of England and Kingdom of Great Britain between 1542 and 1801; and politically united with Great Britain as the United Kingdom of Great Britain and Ireland between 1801 and 1922.
 Today, Ireland is divided between the independent Republic of Ireland and Northern Ireland.
The Queen Charlotte Triple Junction is a geologic triple junction where three tectonic plates meet: the Pacific Plate, the North American Plate, and the Explorer Plate.
 The three plate boundaries which intersect here are the Queen Charlotte Fault, the northern Cascadia subduction zone, and the Explorer Ridge.
 The Queen Charlotte triple junction is currently positioned adjacent to the Queen Charlotte Sound near the Dellwood Knolls off the coast of Vancouver Island.
 10 Ma to 1.5 Ma prior to the triple junction’s current location, it was located southwest of Vancouver Island The movements of the triple junction have been characterized by two major shifts in the Pacific-North American Tertiary plate tectonic record.
 First, at approximately 40 Ma the relative plate motions switched from orthogonal convergence to right-lateral strike slip.
 The variance in location of the triple junction may have also been related to the formation of an independent basin block.
 This formation could have been produced by fore-arc bending of the Pacific Plate, due to oblique underthrusting prior to 1 Ma which produced stresses sufficient to break the Pacific Plate and isolate the block.
 Transpression of 15–30 mm/yr since 5 Ma has been taking place, as well as varying amounts of both transpression and transtension occurring before then.
 To the northwest of the triple junction the Pacific plate currently has 15 degrees of oblique convergence, passing under the North American plate along the Queen Charlotte transform fault zone.
 The Explorer plate is a small chunk of the Juan de Fuca plate that broke away from the Juan de Fuca Plate about 3.5 Ma and has moved much slower with respect to North America.
Charlotte of Mecklenburg-Strelitz (Sophia Charlotte; 19 May 1744 – 17 November 1818) was by marriage to King George III the Queen of Great Britain and Ireland from her wedding in 1761 until the union of the two kingdoms in 1801, after which she was Queen of the United Kingdom of Great Britain and Ireland until her death in 1818.
 She was also the Electress of Hanover in the Holy Roman Empire until the promotion of her husband to King of Hanover on 12 October 1814, after which she was also queen consort of Hanover.
Jane Stanhope, Countess of Harrington (née Fleming; 23 May 1755 – 3 February 1824), was a society hostess and heiress who served as a lady of the Bedchamber to the British queen Charlotte of Mecklenburg-Strelitz.
Samuel Wathen, M.D. (c. 1720–1787) was an English physician who practised in London during the Georgian era.
 He was the personal physician to Rev. John Wesley and may have served Queen Charlotte of England as a male midwife.
Juliane Elisabeth von Schwellenberg (1728–1797), also known as "Madam Schwellenberg", was a bedchamber woman of the queen consort of Great Britain, Charlotte of Mecklenburg-Strelitz.
 She was a well known and prominent profile of the British royal court and household, where she took a dominant position.
 She is also frequently mentioned in contemporary satires, songs, memoirs, diaries and other writings, such as those of Fanny Burney, with whom she was involved in a famous conflict.
 von Schwellenberg was a favorite and confidant of queen Charlotte, and handled access between the queen and various supplicants, which gave her an important influence.
Queen Charlotte was the ship-rigged sloop "Adams", built at Malden (now Amherstberg), Canada in 1807, and purchased in 1812 for the Canadian Provincial Marine.
 She was based at Amherstburg, where she served as a 16-gun sloop-of-war.
 The Americans captured her on 10 September 1813 and commissioned her as USS "Queen Charlotte", but never put her into service.
 They sold her into mercantile service in 1825.
 She traded on the Great Lakes until her owners abandoned her in 1844.
His Majesty's hired armed cutter "Queen Charlotte" served the Royal Navy on two contracts, the first from 10 June 1803 to 13 February 1805, and the second from 17 September 1807 to 17 May 1814.
 She was of 75 tons (bm) and carried eight 4-pounder guns.
 There was also a cutter "Queen Charlotte" that was present at the taking of Saint Lucia in May 1796 by British forces under Sir Hugh Christian and Sir Ralph Abercrombie.