Hi Mystic_angel,
My DD was the same, took her sweet time to start crawling. She rolled everywhere and sort of started commando crawling at around 13/14 months, up on her hands and knees at about 15 months, then walking after 18 months.
Don't let it get you down, some babies are just happy and content without moving around. Taking her to playgroup would still be a lot of fun for her, she doesn't have to be running around to have a good time with other children present.
Personally I was happy that my DD took so long to get going, it means she hardly falls over or walks into things because she has taken to walking very carefully, whereas babies who start running around at say 8 months get into all sorts trouble :P
And now she is tall enough so that I don't have to bend down to hold her hand, another bonus