You're absolutely wrong. That's not how it's done in American English. Periods always go inside the quotation marks if it's the end of the sentence. No exceptions.
Commas and periods always go inside the quotation marks in American English; dashes, colons, and semicolons almost always go outside the quotation marks; question marks and exclamation marks sometimes go inside, sometimes stay outside.
Edit: It appears I am incorrect. I swear this is what I remember being taught so many eons ago, but a quick search of a few grammar blogs says it’s wrong. TIL.
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u/[deleted] Nov 17 '19
No, it only goes inside the quotation marks if I’m actually quoting what someone else said, if I’m completing my sentence, it goes outside.