A 21-year-old premed student died in a horrific Brooklyn car crash early yesterday — and the driver, her 19-year-old boyfriend, is charged with vehicular manslaughter, authorities said.

Carolina Berscakiewicz, of Middle Village, Queens, was decapitated when the 2009 Mazda driven by Sebastian Worwa slammed into a utility pole on Johnson Avenue near Varick Avenue in Bushwick at 3:10 a.m., police and witnesses said.

Her heartbroken dad, Jan, said that his only child was attending Stony Brook University and that he’d bought a car for her birthday and was planning to surprise her with it yesterday.

“She was a great girl,” he said.

Worwa was in stable condition last night at Elmhurst Hospital. Cops were awaiting results of a blood test to see whether he was intoxicated.