It was estimated the bucket of donations contained about $300, though police prosecutor Sergeant Rachel Willemsen told Whanganui District Court that the amount could be anywhere between $50 and $300.
Wanganui RSA general manager Dave Large said Wikohika had done some work with the RSA and paid back some of the stolen money.
"One of our members thought she was a very nice girl," Mr Large said of Wikohika.
"I understand she's undertaken to be on our poppy sellers list for next year."
Wikohika seemed remorseful and genuine, he said.
"These things are unfortunate. It's now up to her to turn her life around - we felt she could do it.
"She's the only one that can do it and it's not going to be easy for her."
The offending had had a "tremendous impact" on the elderly victim, Mr Large said.
As part of Wikohika's work with the RSA, she wrote an essay on the meaning of Anzac Day, defence lawyer Anna Brosnahan told the court. She also paid $50 reparation to the RSA.
She pleaded guilty to another theft in May.
Judge David Cameron said she had learned her lesson - "and done that in a demonstrable way".
Wikohika had no previous convictions and the judge sentenced her to come up if called upon within six months.