Is it necessary to wear all black to funeral?

My old coach just died. I want to attend his funeral but I don't have any all black clothing. I have a black dress pant, black dress shoes but not a black dress shirt. I have a blue dress shirt, it's the only one I have. I'm only 18 and I don't dress up a lot, that's why I don't have a lot of formal clothes. My clothes are casual. Would it be okay if I wear a blue dress shirt? Also is a tie required? I don't have any. I never attended a funeral before so I don't know. My parents didn't even let me attend my grandmother's funeral. Any information would be hopeful, thank you..