"You are flying back to the USA today," the 18-year-old wrote. "Dropping you off at the airport and waving goodbye, it never gets easier. Thank you for the most wonderful adventures these last few months. We even got to celebrate your 20th birthday here in Australia together, hiking through the Great Dividing Range!

"I've known you since you were 16 and every day, from the very first day I met you, you've been my sunshine. I will see you again soon! Thank you for everything, you always make me smile, no matter how far apart we may be. Have fun while you're away, go find lots of manatees in Florida for me! I miss you so much already. You really do mean the world to me."

Aw. First love. Be grateful for FaceTime, kiddos.