Is it when you start learning or when you know enough to make something or when you actually release something you've made on whichever platform you choose?
In the software world, you can call yourself an X developer when you're competent enough in X that an employer would hire someone with your level of expertise as an X developer with no additional training in X.
For something measurable, I would say 90% of the code you write, assuming you write all of the code in your application, does not require the use of Google. I'm sure there are exceptions to this - this number is based on the language you pick. I need to use Google much more often for Java than C# for instance, because Java relies more heavily on methods instead of language constructs, even though I'm much more experienced in Java.
Both of these fail to capture the true scope of the problem. It's very, very easy to fall into becoming an "expert beginner" and never learn advanced language/framework features: http://www.daedtech.com/how-developers-stop-learning-rise-of...