"As for " is it so difficult", it is not considered incorrect. I asked a native speaker and replied it is possible to use it!"
Yes Sarah but only if you use it in the correct context.
eg "Why won't you tidy you bedroom, is it so difficult?"
"Why is it so difficult"
The examples I have cited above change the tenor or meaning of the question completely.
In the context of the question you asked in your OP the use of 'so' is incorrect - use of the word 'very' adds the emphasis, or just leave it as "is it difficult?".
It was the most minor of the mistakes in your OP but a mistake nonetheless.
"As for " is it so difficult", it is not considered incorrect. I asked a native speaker and replied it is possible to use it!"
Yes Sarah but only if you use it in the correct context.
eg "Why won't you tidy you bedroom, is it so difficult?"
"Why is it so difficult"
The examples I have cited above change the tenor or meaning of the question completely.
In the context of the question you asked in your OP the use of 'so' is incorrect - use of the word 'very' adds the emphasis, or just leave it as "is it difficult?".
It was the most minor of the mistakes in your OP but a mistake nonetheless.
:)