Am i and expat? Safer to fil the extensions?

how does the IRS define one to be an expat? I have NOT renounced citizenship, but i simply reside/lived outside the US for more than 330 days of the year, but my address on my tax return has always been US-based.

1. I dont know if I will get the auto-extension.  does it hurt to just file for the extension as a precaution?

2. I’m almost finishes completing my forms on TTax online.  If I file an extension, will it reset what i have filled out and make me do it over again?

3. Is TTax going to charge me for the extension?  Is there a way to do this at no cost on the gov. site?