List of some gifts ideas for her 21st birthday: Portable speaker - JBL Charge 2+ Splash Waterproof Speaker Technology is always a great 21st birthday gift, especially if she’s into selfies and music. If water sports are her thing, the speaker is waterproof and can be used while strolling along the beaches or swimming in the pool. This comes in different colors so you can choose your favorite. Gadget lovers will appreciate iPhone earphones instead as it is