when she had left miss harriet andertons academy for young ladies at the age of eighteen to join the royal household , she had a thorough grounding in music , dancing , deportment , geography and the globes , french , german and the english languages , mathematics including the keeping of accounts and management of servants , as well as religious instruction and artistic pursuits , including watercolours , oils and the decoration of china , together with the art of tambour and painting on silks .