Dear authors:
Thou shalt not, if thou be unsuitably unacquainted with it, insert gratuitous Imitation Middle English into thy stories.
If thou art unlearned and wish nonetheless to utilize it, thou shalt at the least do thy research on the proper forms, for ill-formulation is a weed in the Grammatical Garden.
~P. Siccus
It's not "Old" English, by the way. Old English has bizarre spellings and weird letters like thorns. And even Shakespearean is mostly early Modern.
But seriously, if nothing else is right, at least keep the thees and thous straight. Thee is an object. Thou is a subject.