Worrying about the differences between American and other versions of English feels old-fashioned in an era of global connections.
Yet you should be aware of them.
If you write for English-speakers outside of North America, your words and your meaning will be easier to read, better understood and unambiguous if you follow local use.
If you come from a British English tradition — that includes Australia and New Zealand among other places — you’ll not only feel more at home writing in your own voice, your writing will be more natural as a result.
And that matters online, where a writer’s voice takes on far more importance. Most Americans won’t worry. A few pedants might niggle, others will find it charming.
At the same time, you’ll find words flow more fluently when you are comfortable with your language.
Another reason not to force yourself into using American English is you may occasionally get it wrong. At worse, Americans will spot you as a phony. More likely, you will be misunderstood.
Remember your goal as a writer is to articulate ideas as clearly and efficiently as possible. Your natural voice is the best tool for the job. That’s the one where you can express your thoughts most clearly and reach the audience.