Yep definately strange unless she has something really against the accuracy of the NT Scan but then she shouldnt be pushing her views and choices onto you! I thought maybe if you were a lot older and had a history of downs she may have gone straight for a more accurate test but being 24 with no family history I have no idea why she hasnt done the NT scan firstly :S. Maybe talk to her and ask why she felt the need to book you in straight for the CVS and not offer you the option of a NT Scan? Maybe theres a reason we aren't seeing in her actions that's all I can really think of best of luck and keep well