1995 Toyota Corolla TEMPERATURE GAGE

They generally point slightly below the halfway mark. It could also be the gauge is not working properly.

Take it to any autoparts store and have it scanned to see what the ECM is showing for temp.
It should be in the 195-200 degree range with the fan coming on at 200 or so.

If you replace the thermostat, I always recommend a Toyota thermostat, they have a vent in the thermostat housing which bleeds air from the system. Some aftermarket ones do not and can cause it to run a little hotter.

If the gauge ever gets past the 3/4 mark, shut the engine off, let it cool down and get the problem fixed. You never want an engine equipped with aluminum heads (or any engine for that matter) to overheat.