Wondering if i am eligible for Citizenship?

I have been in Australia since April 7 2001. I was born in New Zealand on February 27 2000, making me a NZ citizen. However, i am wondering if I am eligible to become a Australian Citizen, having been in Australia for 17 years. I am aware of some of the eligibility requirements, but I find my case to be somewhat confusing? The cut off for certain eligibility in Australia for NZ citizens, was 2001 February. So I am wondering if there would be a few months leeway, having arrived only a few months after. Also, I do meet the requirements to be a protected SCV holder. However, I have no documentation that states I am, since the certificates were discontinued in 2004. And I'm almost certain that my parents never got me a certificate from Centrelink stating I am protected SCV.