R my juniors bullying him?

Today one of those kindergarten boy who is now in 1st grade called me an idiot for fun maybe... so i told my juniors who r 13 yr olds that i got called idiot by small kid smiling but they took it seriously and threatened the kid that if he call me idiot next time they will not leave him... then the kid said it was for fun but the boys said f*ck off then to him... i am a 16 yr old and i never expected 13 yr olds to threaten a 5-6 yr old for calling me an idiot