Hey Dempsey, firstly ... how exciting that you're planning your trip!
I came over when I was 22, on my own, on a one way flight to Sydney and I wouldn't change anything. Don't worry too much about having a degree, you will get a job in hospitality/call centre etc. I found it really hard to get into retail despite being a manager in House of Fraser back home!
If you're worried about coming on your own, you should look into this thing that STA travel do. It's like an intro into Oz, first weeks accomodation booked in Sydney, you get picked up from the airport and taken to the hostel and the first few days they help you set up a bank account, tax file number and you get to talk to others that are heading out at the same time on the same group via Email before! It was about 2-300 pounds I think, probably a bit too expensive for what it was but hey, if you're really worried and it's going to help it's worth it!