It may be due to the variety. Early Sunglow is a 68 day corn and typically grows 5 feet tall and has 6 inch ears with 12 rows of kernels. I have grown it before for an early harvest, but other varieties have much larger ears.
Try a 75 or 85 day corn next time.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-