I do not have an opinion. I know my high school buddy trained for years to become a pilot. He started out in small little Cesnas in high school, but did not graduate into jet planes until after college.
That's my only data point.
The principles of navigating on a clear day are the same for a jet as a Cessna. I suggest you ask your pal how long it took to learn cross-country pilotage. Then you'll have a significant data point. And you might be surprised at the answer.
EDIT: mis-typed something.