Need expert advice on strange inclusion in my diamond!!

[beau13]

I got the appraisal this morning, it doesn''t too much, and I''m not sure what some of it means (if it''s good or bad)? So, it states it was graded as a "SI-1, I color, compared to GIA master stones" It was appraised mounted, so weight, color and clarity must be considered as estimates". I get that, but it also states: "a good cut, with a medium thick faceted girdle" Not sure what that means, about the girdle, however I was told it had a very good cut, not just a"good cut"! So...it was appraised at $19 950, does this all sound decent ? Thanks