if i could clearly see the whole body i could probably make a good guess. but i do agree the fins look female shaped, they are a little long, but some females have a bit longer fins. i've seen a lot that do!
lol. it happens. and i just got a male crowntail thats actually about the same colors and markings as yours! and he's a scaredy cat too! ha. but i still think it's possible it's a she. the body shape looks more female than male from this picture. i could still be wrong though.