From one room she took $1200, which was to be used to pay the caterers at the end of the night.
She also stole $60 from a work colleague's wallet after the colleague had unlocked her car for her to sit in.
When spoken to by police, the teen admitted the facts, except for taking the $1200 cash. She said she had taken the items because she liked them.
Defence lawyer Jock Blathwayt said the offending was "spur of the moment".
"It's not as if she has gone on a spree around the district," Mr Blathwayt said.
He did not think there had been any financial loss and most of the stolen material had been recovered.
Mr Blathwayt asked Judge Michael Behrens to discharge the defendant without conviction.
"Every time she seeks employment she is going to have to acknowledge these convictions."
He said the offending was connected with serious problems the defendant was coping with.
"She's undergoing a lot of strain at the moment."
Mr Blathwayt said the defendant was still in school, had never appeared in court before and was considering studying for a law degree. The defendant had suffered enough and been branded a thief at school.
Prosecuting Sergeant Garry Wilson said the defendant was "certainly well enough to conduct the sort of work she was doing at these times".
Mr Wilson said the offending was prolonged and systematic, at one stage she was caught red-handed by one of the complainants and managed to lie her way out of it.
"This defendant has the ability to cope with stress, lie her way out of situations and to go through someone's house during a wedding ... for these people it will be one of the memories of the wedding, being ripped off by one of the workers," Mr Wilson said.
Judge Behrens said a psychiatric report indicated the defendant was in a dissociative state.
"In legal terms, [the] argument is that there was a reduced responsibility in law for doing what you did."
Police argued the defendant could have stopped at any time, "but you carried on, there were separate, deliberate decisions made by you to commit the various thefts," Judge Behrens said.
The gravity of offending had been high and there was not much by way of mitigation.
Judge Behrens convicted the defendant on all eight charges and ordered her to pay reparations, the highest of them $1200.
The defendant was granted interim name suppression.