Who was the first lady to hold the office of Gold Stick in Waiting?

The office of Gold Stick in Waiting goes with the colonelcies of the Household Cavalry regiments (the Life Guards and the Blues and Royals).

The Princess Royal has held the office since 1999. I suspect that she's the first woman to do so, but I can't find any confirmation.

I Should know the answer to this shouldn't I?

Gold Stick is the personal bodyguard to the Sovereign, first appointed in 1678 from one of the Captains of his Horse Guards. The token of office is an ebony staff with a gold head engraved with the Royal Cypher and Crown. Since the 18th century, the appointments of Gold Stick and Gold Stick-in-Waiting have been shared in rotation by the Colonels of the Life Guards and the Royal Horse Guards (later Blues and Royals). Gold Stick for Scotland, first appointed in the 1820s, is invariably the Captain-General of The Sovereign's Body Guard for Scotland, The Royal Company of Archers. There is also a Silver Stick which was created at the same time as Gold Stick in 1678, Silver Stick was Gold Stick's assistant and also chosen from the officers of the Horse Guards. With the elevation of the Royal Horse Guards to Household Cavalry in 1815, the Commanding Officers of the regiments took turns holding the office of Silver Stick. Since the Second World War, the office has been held by the Officer Commanding Household Cavalry (a Colonel) regardless of his regiment.

Sorry it cut off the last sentence.

Silver Stick is no longer used and as far as Gold Stick in Waiting is concerned, The Princess Royal is the first woman or lady to have held this post.