After casting on, it's hard to tell which is the right side or wrong side since you haven't knit any rows yet. But, you can indentify which side is the front by your cast on tail. If you lay the needle out flat, the tail will be either on your left or right side.
If you did a long tail cast on, the tail will be on the left when laid out flat. When you bring the two ends together to make a circle, the tail will come from the first stitch on your
right needle.
If you did a knitting on cast on, the tail will be on the right when laid out flat. When you bring the two ends together, the tail will come from the first stitch on the
left needle.
Either method is a good cast on. Now you're ready to join and start knitting!
