When you select an avatar it is good if you use the same one so everyone knows who you are.
I have had students ask me "how do I make an avatar?"
Here are some avatars I have made.
Lego Avatar - no logon needed.
DoppelMe - the picture in the centre above, no logon needed if you don't save. If you save you need your parents email - do not use the school email if you are in primary.
Bitstrips - me in a red dress - you need to be 13+ to use this primary can not use school email.