I have been recently brushing up my elementary physics concepts, specifically quantum physics. So, if I set up a single photon emitter in the double slit experiment, it is possible for me to see interference (I am assuming), when I thought about this I realized that a photon is mass-less and travels at the speed of light, so time does not affect a photon, therefore a photon can interact with another instance of itself (which in our frame of reference exists in another time).
My question is, is the same effect observable when a single electron is fired at speeds much lower than the speed of light? If so, how? because for this to happen, the electron (which has mass and experiences time the way we do) has to physically be present at two locations at the same time (both the slits)?