That's a tough one! Since you're attending a Christmas concert, you'll want to dress appropriately. I would recommend something festive and stylish, such as a holiday-themed outfit. Think reds, greens, and golds, and maybe a few sparkles. And don't forget your Christmas accessories, like a reindeer headband or a Santa hat! Whatever you choose to wear, just make sure it's something that makes you feel confident and festive. Have a great time at the concert!