what does "shock modesty"mean?
"I'd not sign no papers on it, but generally the first September storm be a three-day nor'easter. The whole country changes. I reckon, one way or t'other, the world. I've heered Oliver Hutto tell o' September storm as fur off as China."
Ma Baxter asked, "Why ain't he come to see us this time? Grandma shocks my modesty, but I do like Oliver."
"I reckon mebbe he's had enough o' the Forresters for a whiles and jest ain't travelin' this road."
"They'll not fight without he acts quarrelsome, will they? The fiddle cain't play without the bow."
"I'm feered the Forresters, leastwise Lem, 'll romp on him ary time they come up with him. Until they git the gal business settled."

Question

what does "shock modesty"mean?
"I'd not sign no papers on it, but generally the first September storm be       a three-day nor'easter. The whole country changes. I reckon, one way or t'other, the world. I've heered Oliver Hutto tell o' September storm as fur off as China." 
Ma Baxter asked, "Why ain't he come to see us this time? Grandma shocks my modesty, but I do like Oliver." 
"I reckon mebbe he's had enough o' the Forresters for a whiles and jest ain't travelin' this road." 
"They'll not fight without he acts quarrelsome, will they? The fiddle cain't play without the bow." 
"I'm feered the Forresters, leastwise Lem, 'll romp on him ary time they come up with him. Until they git the gal business settled."

Answer

It sounds as if Grandma has the tendency to do or say things that shock other people. perhaps she uses foul language, asks impolite questions, or behaves inappropriately.