Without a picture of the bird, I can't tell you whether you have a male or female 100%. But I can offer you some ways to help spot boys.
When it comes to purebred barred birds, males look lighter because they have two copies of the barring gene. Females can only ever have one. Any chick with a red comb by 10 weeks old is male. Pullets don't start to turn red until they are getting close to laying age.
Male specific feathering doesn't begin to develop until about ten weeks old, and it can take several more weeks for it to be visible.