Thinking about buying the Frankie shirt

I found the Frankie vest shirt thing from spirit of Halloween and I’m considering buying it however I wanna know if the sizing is correct or if I should find one a size up or size down

For starters I’m xl and have a bit of a tum and I don’t want to have that tum showing (I just don’t like having my tum show you know)

Anyways, thanks for reading/helping