Localization between Mainland China's 姑娘 and Taiwan's 小姐
姑娘 is more used in northern China or say the mandarin spoken regions. 小姐 is more often used along the coast especially in south.

小姐 gets the meaning of sex worker in 90s. In formal situation, it's still prefrered to use 小姐 rather than 姑娘, which sounds informal and rural.