Is it easier to shift into first if you pull the reverse lockout release?

If so, that is good news. You just need to pull up the boot and adjust the stop at the end of the neutral gate.

If it shifts into first easily if the engine is not running, is your clutch engagement point about where it should be as you release the clutch? If the answers are both Yes, that is bad news. Mine had that problem for years, and it turned out to be rust on the splined shaft that comes from the front of the transmission. The clutch facing disk was stuck in the rust and was not moving away from the flywheel when I released the clutch pressure plate. Wifezilla ground the teeth off reverse every morning as she forced it into gear until the tranny failed completely.

I put in a new clutch and an junkyard tranny with heavy grease on that splined shaft. Smooth shifting since then, except for some clutch cable headaches this year.