I'm not Australian. But I am 5'6", in my thirties (35), and can completely understand about the feelings of loss as friend after friend gets married and suddenly people are looking at you with barely veiled looks of pity.
First of all, congrats on making the first step! I am trying not to be upset about wasting so much time before coming on this journey! So jealous that you have a 5 year head start! :-)
Second, don't try to take in this whole site. Find the places that match you and post regularly (I think daily helps you keep focused, especially at the beginning). Then troll the new posts each day, this is how I discover conversations and info that might help you focus.
Third, if at possible find one or two people in the real world who you can talk to. Having someone at work to eat lunch with, log calories/points with, and talk about going to the gym with is great. My work friend had lost 50pounds before I was even willing to get on the scale and we do completely different programs but the support has been so effective for both of us. She inspires me, I motivate her to keep going. If you don't have someone like this (and I didn't for most of my life), then try to reduce the time you spend with people who don't inspire you on your journey. Try to do other things than eat with them, and if you must eat with them choose restaurants that fit your needs more and where you will not be urged to eat things you don't want to eat right now.
Lastly, this is not a quick trip around the corner... This is a trek up Mount Everest. It will be long, sometimes feel unattainable, and when you finish you will feel incredible joy but know that the journey is not really over. What you need to know, is that you are surrounded here by an incredible group of Sherpas! We may not look the same or talk the same as you but we have to get to the top of the mountain too and we will surround and support you to get there as long as you continue to move forward. Happy travels!
P.S. I love Tina Fey! :-)