My DD picked the number 30 when she first starting playing at 7 y.o. - I think it was because for as long as I can remember when someone asked me "how old is your DD" I would respond, "she is X going on 30!"
Mine too....dd1 has been #6 since she was 10 and is turning 17 soon. Since we have a ton of shirts that are #6 with her last name on the back, dd#2 has decided to be #6 too...lolMy dd was #6 for the past 4 years or so.