Hi Jillio!
I have the exact same thing, only it took me quite a while to get my English brain out of the way to become fluent in Auslan, and to be honest, I still slip up. English is my first language, and I only started learning to sign Auslan nearly 12 years ago...I find it easier to interpret from English to Auslan, except when there are hearing jokes. I have trouble interpreting from Auslan to English.
I also find, there are times where I'll be talking in voice to someone hearing, and I forget an English word, so I end up signing it bse I suddenly start thinking in Auslan...it's quite funny when that happens, and my friends find it really interesting...sometimes i wish I lived i America...I hear there is much more help and services and more Deaf there than inAustralia...I have lots of Deaf friends who lived there for years and sign ASL fluently. I'm jealous! LOL!!
AuslanGirl