Kirsten Duguid was a passenger in a Audi A3 which left an unclassified road, near to the Mains of Arnage, near Ellon, at about 18:20 on Friday.
Another girl, 12, and the 43-year-old male driver sustained minor injuries.
Kirsten's family said "her kindness, generosity and kind hearted spirit touched many".
Police Scotland said officers assisted in removing both girls from the vehicle which was submerged in water. All three occupants of the car were taken to Aberdeen Royal Infirmary.
Kirsten was from the Ellon area.
In a statement released through police, the 14-year-old's family said: "Kirsten was a much loved daughter, sister, granddaughter, great-granddaughter, cousin and niece.
"Kirsten will be sorely missed and we would ask for time to grieve as a family.
"Our deepest and heartfelt thanks go to all first responders and the medical staff at ARI."
Local area commander Ch Insp Elaine Logue said: "This is a tragic incident which will touch the hearts of all those who knew Kirsten as well as the wider community. Our thoughts at this time are with Kirsten's family.
"I would also like to acknowledge the efforts of the emergency services who attended at the scene - it is clear brave attempts were made to free the young girls from the vehicle.
"Members of the public also assisted at the scene and I would like to thank them sincerely for everything they did to help while faced with such tragic circumstances. Police Scotland will continue to provide support to those affected at this very sad and difficult time.
"Enquiries are ongoing and at an early stage and as always I would appeal to anyone with any information, or who saw the vehicle prior to the collision, to contact Police on 101."
Meldrum Academy head teacher Andrew Travis said: "We are all so sad to hear the news of the loss of Kirsten at such a young age.
"She was a gentle and well-respected pupil who was loved by both the pupils and staff throughout the school and was a conscientious student who always tried her best at all she did.
"She will be sorely missed by all who knew her and our thoughts are very much with her family at this time."
The road at its junction with the A948 was closed for several hours while crash investigations were carried out.
A 14-year-old girl seriously injured after a car overturned and ended up submerged in a burn in Aberdeenshire has died in hospital.