In my experience, Barred Rocks are a little "funny". I had one about 10 years ago that everyone here said "that's def. a cockerel" and looked just like your little one, but she turned out to be my very best egg layer. Her comb got big and red early and she was def the most dominant of the 3 as chicks, but she was also the first to lay by almost 2 weeks!
If you can, keep her/him until either definitely crowing or laying, it's kind of like judging a person's likelihood to succeed by who they are as a teenager.