It's too young to have fully developed sex feathering and tails aren't useful in sexing, especially at this age. By the time sickles develop, there are many other secondary sex characteristics evident. Here is sex feathering that he is starting to develop:
You have a pair. These are a blue-sexlinked crossbreed. The males have a headspot and are barred. In the future, pick chicks without the headspot to avoid males! :)