True. But let's flesh this out just a little. While mankind (and apparently angels) were created sinless, we were all created with the capacity to sin. Sin occurs when we choose our way rather than God's way. Even when we disobey God in the slightest, it is sin. But going our own way requires the ability to choose; and that ability was given us at the point of creation. Therefore we may have been sinless in nature in our original creation, but the capacity for sin was placed into us in the very fact that we were given free will and, thus, free choice.