I don't want to bad-mouth the nursery, but I have seen all kinds of plants mislabeled. This tree doesn't strike me as a tree anyone grew from seed as a pre-bonsai. It looks very much like an imported mass-produced Chinese elm. That doesn't mean it's a bad tree - it is actually the species I recommend to anyone first starting out in bonsai.
It looks like a Zelkova schneideriana to me. https://bonsaitreeimg.blogspot.com/2018/12/zelkova-bonsai-tree.html The bark and leaves look like Zelkova schneideriana. It also does look like an elm, but Zelkova schneideriana is called Japanese elm, because it is related to elms and looks like an elm.
That "Zelkova schneideriana" looks very much like a comercial Chinese elm Ulmus parvifolia "chinese malsai" they are often mislabeled as zelkova, for a lot of people were our first bonsai they are produced by thousands by root and branch cuttings and the age its just generic not really his age