Since you have a wide range of understanding on your thoughts and how you behaved in the past , recall an instance wherein you became so unfair to your parents, siblings or friends because you were experiencing adolescence developmental change which was broadening and refining your characteristics that would help in realizing your perspective in life.
Kindly write a letter of apology addressed to the person whom you have hurt the most, but very much deserves to hear your story. Explain to him/her the difficulties you were undergoing during those days. Make this person remember how you behaved and tell him/her the reason why. Also, make him/her understand that you also needed his/her understanding so you would be able to surpass the stage of development.