Yes way

I've had a few people react to me being a new grandma.  Yes, it's true.  I am officially a grandmother with the birth of my son and his wife's baby boy yesterday.  That is how that works.   I really didn't have all that much to do with it but there it is.  And people have congratulated me about becoming a grandmother and I appreciate that but then...like I said...it wasn't anything I did.
There is another reaction that a few people have given me.  I had one friend say Grandmother?!?  No way!  And there was another friend that said they wouldn't call me grandma since I certainly didn't look like a grandma.  Um..thank you?  I'm not sure what exactly I'm supposed to say. 
What do grandmothers look like, anyway?  I mean, really?  I've let the gray grow out in my hair.  I've got enough wrinkles to keep the moisturizer companies in business.  I do needlework and crochet.  I wear a size two and drive a convertible sportscar.  Isn't that a grandma? 
It's this grandma.  Thanks for the congrats.
TT