A primary flight display gives you an attitude indicator the size of the whole screen, a speed tape with a trend vector that shows where your airspeed will be in six seconds, an altitude tape, a moving map, and traffic. It is genuinely superior equipment. In cloud, at night, or on an approach into weather, it is not a close contest.
For a student in the first thirty hours it is a crutch, and a specific one. The trend vector tells you your airspeed is decaying before you have felt it decay. That sounds helpful and it is, right up until the day you fly an airplane without one and discover you never learned what a decaying airspeed feels like through the seat and the controls. Basic airmanship is a set of physical perceptions, and glass reliably delays their formation because it removes the need for them.
There is a second effect that instructors see constantly and it is harder to argue with. Students trained on glass from hour one look inside more. The panel is bright, information-dense and interesting, and the world outside the window is not. Then they fly the Van Nuys pattern on a Saturday with four other aircraft in it, and the traffic that matters is the one not showing on the display.
So: analogue first. Around hour thirty, once attitude flying is instinctive and the scan is built, glass is a three-to-five-hour transition and a genuine upgrade. Do it the other way round and the transition to analogue is longer and considerably less comfortable.