Tuna Shushi

what is better Shrimp sushi, Chicken sushi or tuna sushi?
I want to try some sushi and i don’t know what to eat! i am going to a Japanese restraunt tomorrow and what is better! shrimp sushi, chicken sushi or tuna shushi and what do these 3 taste like?
what do California rolls taste like?
and what is Uni?
Most people say TUNA is the best, although there are different types:
Regular tuna (japanese: maguro): very red color.
Medium-fatty tuna (chu toro): more pink.
Fatty tuna (o toro): lighter pink.
The price goes from low (tuna) to high (fatty tuna), although personally I think medium-fatty is just the best.
Chicken tuna? Never had it, but Shrimp (ebi) is an easy start if you have never had sushi. You can get it cooked or raw.
California rolls are very tasty, with avocado and crab inside and fish eggs (usually herring) on the outside. They’re so good, they’ve made it back over to Japan and are seen in many good sushi shops.
Uni is sea urchin, and is a difficult flavor to get used to. I’d beware of this!
bluefin tuna sushi by Roger part1