there was a thread on this a while back. Different people progress at different speeds, don't be worried about other people. just concentrate on where you are at and where you want to be.
Alot of people who say they could pull 720's their first year, probably had skills they transferred.
They may have been good at trampolean before, good at fruitboots, good at snollerblades, whatever.
Once you've gotten the feel for skiing its not real hard to transfer your other skills to it. If you do not have experience in other areas then chances are it may take you a little longer to catch it. But once you've got air sense and you've got the basics, it will come.
This year I went from throwing sketchy 360's off small jumps to rocking 900's grabs, rodeo 5's, lincolns, whatever.
Just work on the basics and it will come, and don't be concerned about other people.
Eat. Sleep. Breathe. Ski.