There was about $300 in the bucket, none of which was recovered.
Wikohika told police she knew her friend was going to steal from New World, but thought it would be chocolate.
Judge Dugald Matheson said he was in Sydney at the time of the April 17 offending.
"It's a big thing over there," he told Wikohika, referring to Anzac Day commemorations.
"You're very lucky you didn't raid a tin over there, because you would have been lynched.
"This is a serious matter, because it shows disrespect to servicemen." The elderly lady who was collecting at the time was "traumatised" by the theft but uninjured, said Mr Butler.
One of the other two offenders was being dealt with in the youth court. It was unclear whether the third person would be charged.
Wikohika was remanded to May 27 for a restorative justice conference to be held.