Best Options for American and Austrailian Wanting to get Married?

So, I'm an American man, I'm dating an Australian woman and I'm wondering if things get more serious, to the point of us wanting to get married, what is the easiest path forward?  She's 70/30 in favor of staying in OZ, I'm 60/40 in favor of us living in OZ as I think it's a better quality of life and a better place to raise children.

If we want to end up living in OZ, would it be best to get married in the US while she's visiting me or better to get married there?  Would it make a difference either way if she were pregnant?  Hopefully somebody has been through something like this and has some insight.

Also, I have a 21 year old son, he would like to live where I am so I don't know what options would make that easier.  For example her as his "step mom" being able to sponsor him.   
Hello TucsonAZ,

Welcome to Expat.com 1f60a.svg

Thank you for posting your message here.

I can see that this is a decision that deserves a lot of thought and may not be so easy to make.

Fortunately, you are on the right forum because I am sure that the members who have already gone through it will be able to help you by sharing insights and experiences.

In the meantime, I suggest you read the Living in Australia guide to get some tips and useful information.1f609.svg

All the best,

Cheryl
Expat.com team