It is not citrus or mango. Seedling citrus can get that tall but they are rarely seen anymore. I remember a few old seedling groves (citrus) and they were about the size and form of a field grown water oak. The lateral veins in a mango leaf are a lot more prominent and the leaves are not as v shaped.
This leaf is thick, waxy, and smooth and the midrib is relatively sharp and raised, more so than that of a loblolly bay. I was surprised to find any growing as far north as my location in central Florida.