Clutch engaging early (close to floor)

My clutch started engaging really early (close to the floor) a few days ago, and it suddenly became difficult to shift into 1st or reverse, and sometimes the pedal doesn't come up all the way or is slow to do so. I searched around, and most posts/sites say bad slave or master cylinder, and check for leaks (no leak -- fluid is full, but dirty), but I also came across this which says replace the flywheel: (I can't post links, but the title is "Clutch engages suddenly and clutch pedal feels squishy sometimes")

The dealer looked at it and told me I need a clutch overhaul because the disc is worn. Am I just being taken for a ride, or is that actually a possibility?

Thanks for any advice!