Kindergarten will be lovely. Your daughter will meet all of her new classmates and then slowly find the ones she enjoys the most.
Birthday parties are a great way to meet the other children and their parents. In most schools invitations must be handed out to everyone in the class or none at all. It's a ver good policy that allows no one to be left out and everybody to meet everybody.
If your daughter is lucky enough to have a birthday in the beginning of the school year, then you get in on the very beginning of that process. You meet all of the kids early in the year so you can steer her away from some and make private playdates with the others that you approve of.
So, definitely have a birthday party and invite everyone. That's how you control her friends.