Connor Chapman has been found guilty of murdering Elle Edwards, who was shot outside a pub on Christmas Eve.
Chapman opened fire with a sub-machine gun as he targeted two men in the culmination of a gang feud.
Elle Edwards was an innocent bystander who was enjoying a night out with friends when she was shot.
Chapman was also found guilty of attempted murder, two counts of wounding with intent to cause grievous bodily harm, one count of assault occasioning actual bodily harm, possession of a gun and ammunition.
Co-defendant Thomas Waring was found guilty of the possession of a prohibited firearm and assisting an offender by helping to burn out the stolen
Mercedes used in the shooting.
Chapman will be sentenced on Friday, and the judge said he would give a new beginning to the family.
A man named Chapman has been convicted of the murder of Elle Edwards, who was shot dead outside a pub in Wallasey, Merseyside in 2021.
During the trial, it was revealed that one of the witnesses, Karl Chapman, had been accused of the murder, and had claimed to be at home all night on the night of the shooting.
However, CCTV footage showed a man matching Chapman's description near the home of the other suspect, Nathaniel Waring, who was later attacked in prison by another inmate.
Waring was not convicted of the murder but was found guilty of handling stolen goods in relation to the theft of the car used in the shooting.