My 1996 Ford Escort shift lever sometimes won't move into 1st gear position unless I turn the motor off, then start in that gear. It also, sometimes, won't move into any of the gear positions and I have to coast to side of road, kill engine and start over. Recently, it has started to, sometimes, start up in gear but start moving even with the clutch pedal still depressed; additionally, when this happens, the lever will not move from that position at all (either 1st or reverse, of course), not to neutral, nothing. What is going on? I do mean the stick itself won't move.
From your description it sounds like something about your clutch is failing. It may be the clutch itself or some part of the clutch system that disengages the clutch.
First gear on older cars is normally not synchronized. When the clutch starts dragging for any reason the first gear may be the first to start having issues because the other gears can overcome the dragging with their synchronizers.
When the clutch gets really bad then no gear will work well or at all.