The mother of Sophie Lancaster says she feels "nothing but contempt" for her daughter's killers.
Ryan Herbert, 16, and Brendan Harris, 15, kicked the 20-year-old to death in Bacup, Lancashire, simply because she was a Goth, Preston Crown Court heard.
The pair, said to have acted like "wild animals", were convicted of murder and will be sentenced on 28 April.
Sylvia Lancaster said the death of her daughter had also left her doubting if she could continue as a youth worker.
Neither of the teenagers knew Ms Lancaster or her 21-year-old boyfriend Robert Maltby, who survived the attack.
The court was told their only motive was that they simply looked different to them.
On Sunday, Ms Lancaster said: "To choose to beat and stamp a young girl to death just because she looks different and show no remorse afterwards is just so sick.
"I feel nothing but contempt for them."
Speaking after the conviction, Ms Lancaster, said she hoped society would reflect on the killing and examine ways of avoiding a similar crime in the future.
Now the 52-year-old is questioning her role working with young offenders at youth advisory care service Connexions.
She said: "I've always cared passionately about trying to help young people like them [Herbert and Harris] to find a way out of the cycle of violence and crime a lot of them have grown up with, but I don't know if I can continue.
"To do that job, you have to be totally non-judgmental.
"Now, I don't know if after losing my daughter in such a senseless way, I can look them in the eye and bring myself to feel enough sympathy and understanding for them.
"I just don't know how I feel to be honest."
Sophie Lancaster, a gap year student, died from serious head injuries two weeks after the attack in Stubbylee Park in the early hours of 11 August 2007.
Harris, of Spring Terrace, Bacup, had denied the murder charge. He said he had punched Mr Maltby once after drinking two litres of cider, a bottle of strong lager and some peach schnapps.
Herbert, of Rossendale Crescent, Bacup, who had also been drinking alcohol throughout the night, admitted murdering Miss Lancaster before he was due to go on trial.
Both teenagers pleaded guilty to causing grievous bodily harm to Mr Maltby
Three other youths, two aged 17 and one 16, who cannot be named, also pleaded guilty to assaulting Mr Maltby.