Answer
See answers.
Work Step by Step
The wavelength is about the same order of magnitude as the width of a typical doorway so yes, you would notice diffraction effects.
We find your speed using equation 27–8.
$$\lambda=\frac{h}{p}=\frac{h}{mv}$$
$$v =\frac{h }{m \lambda } $$
$$v =\frac{6.626\times10^{-34}J \cdot s }{(68.0kg) (0.50m)}=2.0\times10^{-35}m/s$$
The time required to pass through a doorway moving at that speed, assuming that traveling 0.25 m means you are “through” the doorway, is unimaginably long.
$$\Delta t = \frac{L}{v}=\frac{0.25m}{2.0\times10^{-35}m/s }\approx 1.2\times10^{34}s\approx 4.1\times10^{26}\;years$$