"It is our faith that keeps us going, we would never cope otherwise. Lots of people have given us cards and flowers. God is with us and in our family," Margaret Mizen, a devout Catholic, was quoted by the Daily Mail as saying.
Mrs Mizen's comments followed a memorial Mass at St Thomas More Catholic Comprehensive on Monday, which would have been Jimmy's last day there as a pupil.
Jimmy, an altar boy and the thirteenth teenager to be murdered in London this year, was stabbed in an unprovoked attack at the Three Cooks bakery in Lee, south-east London on Saturday morning - the day after his sixteenth birthday.
Mrs Mizen said Jimmy's priest had described him as a saint.
"In the 16 years and one day, I've had him I've never once told him off," she said.
Jimmy's father, Barry Mizen said the family had the memory of telling their son they loved him the day before he died.
"On the night of his birthday he was just going out with some friends, we cuddled him, nothing unusual, said we loved him. And that is great, that's a great memory for me."
Margaret said she did not feel angry at her son's attacker.
"There is so much anger in this world, and it is anger that has killed my son.
"If I'm angry then I'm going to be just doing exactly the same as this chap. We have got to get rid of all this anger that is around."
Earlier on Monday, police made a breakthrough in the hunt for Jimmy's killer when a witness, who had been in the shop at the time of the attack, came forward after a number of police appeals.
