Help me pick one

I have been having a hard time (very hard ) with picking a niche for my store, so I have cum up with three of these niches and I want you to decide which one is best for business. There are Fashion, Fans Merch and Vlogging accessories. Please help me Pick one.
OK thanks, please I have a question. If i include other big brands' trademarks (like the marvel for an example) in my domain name did I break any trademark laws