Rosa began freelance writing when she was a student at the University of Toronto, for The Strand, a student newspaper at Victoria College. Eventually, she also became their Editor of Photography.

Whilst living abroad in London, Rosa pitched an idea to Lonely Planet, and then started doing some travel writing for them. When she moved back to Canada, she also picked up a few pieces with Taste Toronto. Eventually, wanting to create longer-form content that was thoughtfully researched, she began writing for Brown History.