Jermaine Jackson -- If Paris Is In Love ... I'm Down with Marriage!!! (VIDEO)

Jermaine Jackson has a laissez-faire attitude when it comes to his niece Paris Jackson, because he's down with her getting hitched at 17 if she's truly in love.

Paris and BF Chet Castellaw were photographed Saturday coming out of a Calabasas coffee shop and she was wearing a ring on her engagement finger. Thing is ... there are no diamonds in the setting, and it would seem the 18-year-old soccer player would show due matrimonial respect.

Nonetheless, check out Jermaine and his snappy duds.