Hey, you’ll love it. There are travel agencies on every corner of Iceland, so if/when you go, you don’t need to worry about getting tickets beforehand. Just find a travel agency, which I guarantee will be easy, ask for Blue Lagoon tickets and they’ll set you up with a bus to take you there if you need it, and you’re all set. My family and I went there in a pre-flight home tour, which is nice, but I don’t recommend it because all you want to do after the Blue Lagoon is sleep. It’s mostly packed, but it’s huge, so don’t worry about it. Have fun!