Young women have traditionally been offered cheaper car insurance than men as their accident rates tend to be lower, leading experts to predict that younger women will be among the worst affected by the changes.
Confused.com's figures also showed that the typical premium for a young male driver dropped to £2,960 by the end of the year, a £354 decrease from three months earlier.
Gareth Kloet, head of car insurance at Confused.com, said: "It's clear to see that the insurance industry has both reacted and prepared for the well-documented and anticipated change in legislation during the last quarter.
"On average, males aged 17-20 are now paying £2,960 for their car insurance, compared with £3,829 in the second quarter of 2011, meaning men are now having a greater chance of getting on the road as their premiums come down."
The car insurance index, compiled by Towers Watson, uses quotes submitted on the Confused.com website, taking the average of the best five deals from each quote.