I think 1 or 2 gallons of fuel seems kind of high. Granted, my experience is limited to the 5 trainees in my "class" this year, but I think there are factors that impact the average.

Video games - Most people who have played video games have less of a problem with orientation than those who never have.

Flight Sims - The two people with sim experience in my class (me and another guy) soloed in about 6 - 12 flights. The three without took a great deal longer. One older gentleman had been trying to land for two years.

The instructor - I had a variety of instructors, several took the plane up (really) high and then said have at it. The best talked me through a specific set of exercises and after getting it up to altitude talked me lower and lower until I was able to land.

As long as you're having fun, its not a contest to see how fast you can solo.

GB