Elvis met Priscilla in the 1960's, when she was either 13 or 14 in Germany, where her parents lived and he was stationed in the army. He wanted to bring her back to the states to live in his house, and (her) parents gave him permission, since (his) parents would be living there also. They got married in 1968/69, when Priscilla was 21 years old and her daughter was born exactly 9 months later. They got divorced about 3 years later.
Elvis died August 1977 due to a drug overdose, since he was addicted to opioads like many people today are.
Was he dating young girls? Maybe or not? But, unlike today, dating young underage girls would make you a pedophile, or get you arrested, or statutory rape, depending on the age. Things have changed a lot over the last 10 to 20 years vs over 40/50 years ago.