Is there a graft at the base of the trunk near the roots? It is possible the "knot" you see is a graft of the variety that you wanted, but typically the nurseries will place this graft at the base of the trunk, not 3 feet up. I just want to make sure we don't lop off the desired variety! Assuming the "knot" is a disease of some sort and not a graft, then it would be best to cut it off. But if it is a graft, then no!

no the graft is at the base of the tree. i planted it just below the graft so the rootstock doesnt sprout. no this is at the top. thanks for answering

Cut it just above a bud that's facing north if possible so it grows straight.