If you have different breeds, you may be seeing more of a breed personality difference. Or you might be seeing an individual personality difference. Or you may just have a chick who is feeling good enough to check you out. (Remember, birds have no fingers, so they "feel" you with their beaks.)
I raise several breeds, and Ameraucanas are among the more assertive chicks, compared to Delawares and Crevecoeurs. Not necessarily aggressive, just less afraid.
You will probably have to wait a while to see sexing signs. I don't know of any early signs in Ameraucana chicks. I would like to know if there are any, too.
In Crevecoeurs, starting about the first week after hatch, boy chicks will challenge one another by getting in one another's face and standing as tall as possible; sometimes they accidentally challenge a Crevecoeur girl, who reacts by staring at the challenger in disbelief ("What, you can't tell I'm a girl?") or by walking away in total disinterest. This Crevecoeur behavior is 100% accurate in predicting sex, in my experience. I have not ever seen Delaware or Ameraucana chicks do this until much later, when the feathering is already starting to give the boys away.