My 1999 ST Patrol hasn't had first gear for about five years now and it hasn't been a problem, but I have now noticed that when accelerating to change into a higher gear the revs suddenly shoot up at around 2000 revs like I have put my foot on the clutch with my foot still on the accelerator.
Sounds like your clutch is slipping, possibly from being asked to start off in a higher gear for the past five years.