Hmm, assuptions made: most young guys join Farkin when they are about 15, so if you joined in 2007, that makes you about 20, which stacks up with you having your own place with your girl for 18 months or so about 5 months back...
If there's "nothing wrong" but you don't have the desire to follow your girl's dream and shift to Melbourne, then although things are okay, you're not wed heart and soul to being with her. Not that I am critical of that, just trying to figure out where you're at.
Heck, I'm 40 and I'm just starting over, after leaving something that wasn't right for me (took me 15 years to find the exit and turn the doorknob). Head OS, have some fun, chase your dreams for a bit and see what happens. I can remember thinking that turning 28 would make me ancient. Now I'm 40, I don't feel that old. At 20 or thereabouts you've got your whole life ahead of you, and a 2 year relationship give or take a bit, while significant, is not a life commitment.
Life has a habit of throwing funny situations in your path, no matter if you're ready for them or not. So go live, and see what cards you get dealt... Can't put your life on hold for what might happen some time in another 3 years or so.