So, you can get it into second gear, but requires a great deal of effort...and if you just shift normally, it sounds like grinding? Might've bent the shift rod for 1-2, or the shift fork pads are gone...either way, you'll need to pull it apart...
FWIW, the teeth between gears are always meshing-except reverse, so if the car doesn't sound like it's eating ball bearings just rolling along, the gears themselves aren't lunched. As soon as the car starts rolling, the mainshaft and countershaft are spinning, and gears are turning together at different speeds individually. When you select a gear, the synchro assemblies mechanically link them through the shafts. The grinding sound is actually from the blocker rings (or some call them dog rings) engaging the synchro...if the clutch gets engaged before these are together, you get grinding.