Is there REALLY such things as "Heavy bones"?

Not Heavy Bones In A Big Bones Girl Which means Im Big Built Body, Not Fat More Average, Like I Am a 5"8 13 Year Old, Who Is 10.10 Which My Bmi Says Im A Good Weight And When I Try Any Loose Weight I Put It On And When I Try Gaining I Loses, Its Odd But Bones Are Bones. The Weight Is Normal To All Women, So Its No Excuse xD