To be perfectly honest, I wouldn't worry about the fish being raw. In fact I wasn't big into fish but once I tried Sushi I grew a love for fish. Sushi in general is very rich tasting and the fish itself generally doesn't have that 'fishy' taste to it (I don't like fish like that anyway!). Sushi chefs are generally very particular about serving Sashimi/Sushi very fresh and ensuring that everything is ok

Honestly, give it a go and you will be suprised