Why Key of D ....from beginning? and not C

Hello David,
Just wondering why D and not C to start with? I know there is a good reason. My short experience with my D seems that the first 3 holes blow and draw take more effort than C.
Also bending even with pucker on 2 and 3 take much greater effort and bending or no ... my tongue block seems to have much less strength...at least now.
Maybe its my harp...but i know that is a mistaken belief of beginners.
Thank you!
Steve