The line between confidence and arrogance can sometimes be fine. It sounds to me like your 7-year-old has blurred the line. Let's not be too quick to judge. She has been through a major transition. It is hard, certainly challenging at best, to leave the comfort of one's home, school, teachers, and friends and have to adjust to a whole new world. Also, your youngster lived in a capital city where girls can be competitive and rivalrous with fashion, academics, achievements, and materialism. Moving to a regional town may have left her a bit lost at how to find her place or position within her new social group.
You need to have honest straight talk with your daughter. Tell her you know she wants to make new friends and that is a good thing. Help her understand that bragging and showing off makes the others feel put down and will push kids away. Offer her some suggestions for appropriate social overtures. Offer to host a play date with one or two girls (7-year-olds generally play girls with girls and boys with boys). Make the play date short and super fun. For instance, the girls can prepare and bake chocolate chip cookies. While the cookies are in the oven, they can do a short art activity or play with dolls. Then, they can eat the cookies with milk and the play date is over. Short and sweet bonding! If this fails, your daughter may need the help of a skilled school counselor or child psychotherapist to provide her with more extensive support and guidance. Good luck!