Andrew Hall, 18, was sentenced to life in jail with a minimum term of 10 years for the fatal attack upon Megan-Leigh Peat, 15, in Ampthill, Bedfordshire, on June 9.
Miss Peat, a pupil at Harlington Upper School near Dunstable, received 60 stab wounds to her head, neck and upper chest in the attack.
Hall admitted stabbing her in the head and body at the house of a mutual friend after they had spent the evening drinking in pubs.
She died from her injuries and severe blood loss despite the efforts of the emergency services. Two knives, including a bread knife, were found next to her body.
Judge Richard Foster, sentencing at Luton Crown Court, told Hall: "Megan Peat will never experience the thrill and success of exam results, going on to higher education, or perhaps being a bridesmaid at a best friend's wedding or an 18th birthday party.
"Her life ended in your hands at 15 years old.
"Only you know why you did what you did that night and what the catalyst was for such a ferocious attack.
"It is clear you were jealous of her innocent friendships with others."
Hall, of Flitwick, was treated in hospital for hand and arm wounds for several days following the killing.
Miss Peat's family released a statement describing their daughter.
It read: "Megan was a healthy, vibrant, loving and caring person who was very much loved by all her family and all her many friends. She had her whole life ahead of her.
"Before her untimely death we were an ordinary family leading an ordinary life.
"Since that fateful day our world has changed beyond recognition.
"The pain of losing our beautiful daughter and the tragic and awful way she died will stay with us for the rest of our lives."
Hall was released by the Potters in May at the conclusion of his three-year scholarship but had been expected to sign professional terms for them next season.