Ashleigh Hall was more than a daughter she was a best friend, her mother Andrea said.
As convicted sex offender Peter Chapman was jailed for the rape and murder of the 17-year-old, Andrea Hall described her daughter as a "typical teenager.
Mrs Hall, 39, said the Darlington teenager "talked and talked and talked" and loved being with her three sisters.
"Ashleigh wasn't a bad kid. She was naughty. She made one mistake and has paid for it with her life," she said.
Mrs Hall said her eldest daughter helped to raise her three younger sisters, Olivia, six, Ellie, four, and Evie, aged one, and was studying to be a nursery nurse.
"Me and Ashleigh were on our own for 11 years. She was always very grown up for her age because it was just me and her and she was brought up around adults.
"When I had the girls she was like their second mam. She used to look after them for me if I needed to be everywhere, and she loved them.
"She would have been 18 just after Christmas, she had her full life in front of her.
"Ashleigh was my rock. Because of that she was also my friend as well as my daughter.
"She helped me constantly with the others. She baby-sat, ironed, changed nappies, she did everything I asked her to.
"She fed, washed and bathed them because she had a loving nature. I would give her a little bit of pocket money for helping round the house and she used every penny to top up her phone to chat to her friends.
Andrea Hall said she was still coming to terms with her daughter's murder
"She was always talking and texting and on her computer.
"As soon as she got in from college she would be on the computer using MSN to talk to her friends even though she had been with them all day."
Ashleigh, a former Brownie and Guide, was a "typical teenager" who used to play her favourite music loud and dropped her clothes on the floor, her mother said.
Ms Hall said: "She just took her clothes off and left them on the floor thinking it was my job to pick them up."
The teenager's bedroom was dominated by pink, with a Playboy bunny duvet cover and curtains, and photos of friends and family all over the walls.
Ashleigh, an animal lover, did not have a boyfriend, her mother said.
She said she was still trying to come to terms with her daughter's murder and that she was now living for her three remaining children.
She added: "It still doesn't feel real. If it wasn't for the other three then I wouldn't be coping but because I've got three other girls then it is just keeping me strong.
"I've got a good family."