First person camera creation?

The reason why you can’t look up or down is because you set Look_Turn to -1.0 when it should be 1.0.
The same thing with Look_Up which should be -1.0.

Should be:

Look_Up - Mouse Y = -1.0

Look_Turn - Mouse X = 1.0

And your S setting should be -1.0 and not 1.0.

Move_Forward - S = -1.0