We never had the driving course in the school parking lot, they just took us directly to the road.
At the time (about 47 years ago) the high school I went to was pretty rural, so, as you posted, most of the kids already had much driving experience on backroads, ranches, farms, etc.
And yes, we also had to go to the DPS to test for our learners permit, at age 15. Passed that the first time, as well.
That summer (1978) we drove back to No Cal to visit friends. We went through Colorado to see the sights.
We drove our ‘70 Chevy Camper Special with the cab over camper, and pulling a small tent trailer behind, as our family of six had outgrown the camper. Mom, Pop and lil’ sis slept in the camper, and myself and two younger bros slept in the tent trailer.
Anyhoo, my folks let me drive the whole shebang on I-70, through the mountains of western Colorado, and all the way to I-15 in Utah.
I drove a good bit on the way back home to Texas, as well, without incident.
On a side note, I’m hearing these days that many kids don’t even want to learn how to to drive and get a drivers license, or they’re delaying it for a while.
Man, when I was in high school, everyone was chompin’ at the bit to get their drivers license, boys and girls.