Feeling Guilty About Daycare

So I am ALL about the staying home with your kids, but sometimes I feel guilty about not sending Samantha to daycare. I see all these other kids who know how to line up to go outside or sit down for snack with all their friends. Samantha is the only one in her class at church who doesn't go to daycare. It is so weird to see how she interacts differently with the kids. Whereas, the rest of the kids will play together (even just parallel play), Samantha doesn't want anything to do with anybody else. Even when I am not there, they say she entertains herself and plays quietly without anyone. When I am there, it is, "Mommy, Mommy, Mommy." She has friends and she goes to play groups. I get her out into the public to meet people, but if there is more than one person present (other than me), she gets sort of shy and walks away. What do I do? Is it just her personality? I feel so bad that she isn't like the other kids. She really isn't like them at all. She is much quieter and prefers to do different activities than the other kids. Is that my fault?