While you think she may use driving as a way to act cool, once she actually gets behind the wheel and gets some driving time in, she may realize how overwhelming the responsibility is. That all being said, I think almost every state has a minimum number of hours that a student with a learner's permit must practice driving before they can get their license. Also, whoever does the behind-the-wheel instructing will have an influence on reminding her of the great responsibility that comes with driving... meaning, hopefully they'll put the fear of God in her. I know mine did.
As a parent of newly learning-permitted drivers many years ago, I insisted that those hours practicing take place in a wide variety of situations: traffic, highway driving, nighttime, snow, rain, etc. I started them out in an empty parking lot at night and didn't hit the road until I felt they had good control of the car. Even then, I found driving at night for those first few learning hours was easier on my nerves because there was less traffic around. We had a large neighborhood near us that had a parkway (max speed limit 30mph) that split it in half for about three miles. We'd drive up and down that because it gave them a feel for controlling the steering wheel in turns and corners. And we didn't have to worry about too much traffic riding the rear of the car.
I know many parents aren't willing to commit the time required by their state - I know parents who signed off on hours that they didn't supervise; I think that's shameful.
I have to admit that I am wondering about your wife's side to this. As a mom, I was the main taxi for my kids. We lived JUST under 1.2 miles from their high school, so they didn't qualify for the bus, and we lived in the Midwest where it's dark in the morning when they'd need to walk to school, and many times sidewalks weren't shoveled. So I drove them to school. I often had to pick them up after school, then return them for extra-curriculars, and pick them up again when those were done. By the time they turned 16, I was so tired of hauling them around, that I was the one who insisted they get their driver's license. Our state also had a law on how many people could be in the car with them in the first couple of years they had their license. But yea, as the main form of transportation, you bet I wanted them getting their license at 16. I took #1 on the day of her 16th birthday, and #2 on day 2 (there was a holiday on her 16th birthday so offices were closed).
Also, a LOT can change, maturity-wise, between the 15th and 16th birthdays. A year is a lot of time at that age.