Letter confusion

Yesterday at my mom's house, Shelby hugged Coleman and told everyone, "This is my friend Bubby. He's my best friend." So then today in the car after picking up Coleman, I said, "Shelby is Bubby your BFF?" She got so mad saying, "No this is NOT my BTF mommy! This is my Coleman!!!!" That was kinda funny, but I just dropped it. Then, we got home and Jeff came out to help us all get out of the car. When he picked Shelby up, she immediately told him, "Daddy, Mommy said Coleman is my ARP but I said he is NOT my ARP." (Jeff is laughing) I say, "No Shelby I said he's your BFF" and shelby says, "NO HE IS NOT MY QRS Mommy!!!!" Well, she may not have her letters down but she knows what letters are. haha