Amy Simpson, 18, died when her car left the road near the village of Dalavich, on the banks of Loch Awe, on Tuesday.
Miss Simpson, from Cowdenbeath in Fife, was with four other women passengers who escaped without serious injury.
Her mother Angela Simpson said her "gorgeous girl Amy" was "my best friend, my soulmate and my rock".
She said: "She made me so proud.  One day I will make her as proud of me as I was of her.
"I am absolutely heartbroken and it's hard to find the words at this distressing time to express just how much I will miss her.
"Rest in peace Toots."
Miss Simpson's black Peugeot left the road at about 18:40 on Tuesday and the car ended up in the River Avich.

The 27-year-old's career, which started at French club Montpellier, has taken him to Ukraine and Germany and he spent last season on loan at Ligue 1 side Nice.
"I've joined the biggest club in Turkey and after two years without the title I hope my coming will change that," Belhanda told the club's official website.
He becomes Galatasaray's third signing of the season after Brazilian defender Maicon and French forward Bafetimbi Gomis.
The 2012 BBC African Footballer of the Year nominee made his debut for Montpellier in 2009 and went on to make 144 appearances, scoring 29 goals for the club.
A member of the Montpellier side that won the French Ligue 1 title in 2012, he joined Dynamo Kiev from Montpellier on a five-year deal in July 2013.
He scored 11 goals in 88 appearances for the capital side, winning the Ukrainian League and Cup titles twice.
Belhanda spent the last two seasons on loan with German side Schalke and French outfit Nice.
A former French youth international, Belhanda chose to represent the country of his parents Morocco in 2010 and has two goals in 30 appearances for the Atlas Lions.

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The home side finished on 151-7 in reply to Glamorgan's 176-5, despite Michael Klinger's 52 off 34 balls.
Miller struck his 50 off 33 including three sixes, as the Welsh County moved to the top of the south group table.
Rudolph's 51 off 46 was a more measured effort, while Sri Lankan seamer Thisara Perera bowled tightly for his 2-25.
Glamorgan moved ahead of Surrey on net run-rate at the top as Miller showed his international class despite a patchy wicket which benefitted the medium-pacers.
Klinger threatened for a while to get Gloucestershire in the chase in front of a packed home crowd, but Colin Ingram took 1-18 in a mean four overs while Graham Wagg claimed his 100th T20 wicket and the home side fell short.
Man of the match David Miller told BBC Wales Sport:
"I'm very happy to be one (win) from one, and looking forward to the next four games. I was a bit nervous for a couple of balls, it took me six or seven to get going but it's nice batting with Jacques Rudolph who has a lot of experience.
"It's always good to hit the pavilion, the one I got out I was trying to hit over the top of the apartments, but it's nice to hit a few sixes and get the run-rate up.
"Every single game I get nervous, but it's what you do with the nerves and where you take it - it's a short stint to make an impression but I'm just trying to play my game and enjoy it, which has been really easy with this changing-room."
The mother of a teenager who died when the car she was driving plunged into a river in Argyll has described her as the "perfect daughter".
[NEXT_CONCEPT]
Moroccan international Younes Belhanda has joined Turkish giants Galatasaray from Ukranian side Dynamo Kiev on a four-year deal.
[NEXT_CONCEPT]
Fifties for Glamorgan debutant David Miller and captain Jacques Rudolph proved key as they beat Gloucestershire by 25 runs in Bristol.