Two years ago, when i was 20 years old, I went backpacking around the world on my own. I'm not a loner, or extraordinarily independent, and I did just fine. It seem like people exaggerate what difficulities you will meet along the way. Things always works out. Loneliness wasn't really a big problem, but I did get a bit tired of temporary friendsships. There's plenty of people to hang out with, but they're all loyal to themselves and so will you be. But that's something you'll get used to and there's no problem keeping in touch with family and friends trough emails.
You seem like you're totally up for the challenge. If you kepp this attitude, this will be an exclusivly positive experience for you. You'll learn so much about yourself. What you see and do isn't the biggest experience; but rather being on your own and being free and independent. I came home with a feeling of increased self-efficacy.
You should however travel with some funds. There's no problem traveling on a shoe-string, but you should have some kinda bakcup if things get rough. Have at least enough money to get yourself an airticket from where you are and home. My second advice would be to carry money or means to get money seperatly. Say if you have two credit cards: keep one in your backpack and the other one on your body.
My travelroute was Norway - Netherlands - Mexico - Belize - Guatemala - L.A - Tonga (South Pacific) - New Zealand - Australia - Singapore - Malaysia - Thailand - Cambodia - Laos - Thailand- Norway. If you have any questions about any of these destinations, go ahead and ask. My route was maybe a bit too extensive; it was a lot of work moving that much around and it cost me alot more money but I got to see and experience so much more.
The US was the only place I didn't feel really safe actually. I learned that most people don't wander the streets of Downtown LA at night
