I have a cd of Gershwin playing Gershwin and he plays this at a much faster tempo.
... it does not have to be Bernstein-like slow.
While the third movement took a rather short time to record, to my mind the first one is a real candidate for a recording composed of several takes, because of all those jumps. So I took a slower and less "decisive" attempt to get it right in one take.
I have a recording with pianist Leon Bates (Naxos) who also takes the second movement very slow and with much rubato. But I think the piece lies somewhere in between the "Andante" and "con moto".