21 Best 21st Birthday Gifts for Her. Turning 21 is a major milestone worth celebrating. Here's 21 trendy 21st birthday gifts for her and cute 21st birthday gift ideas for her to celebrate entering adulthood! These 21st birthday gifts for best friends, 21st birthday gifts for daughters, and trendy gifts for 21st birthday girl will make your friends or family feel special on this big day and help them remember turning 21 for years to come. Includes cute gifts for 21 year old girl, gifts for 21 year old daughter, 21st birthday present ideas, 21st birthday present ideas for friends, 21st birthday gifts for best friends.