The attempt to transcribe Hebrew script of any kind (There are several) to a tattoo would be difficult. I did describe the possibilities to another thread some time ago, but would rethink that advice after discussion with my knowledgeable Jewish mentor, Tovi...
Firstly. the Hebrew written script, as stated is never done other than right to left. An inscription the length of your statement would probably only be accomplished
vertically somewhere on your body and so would have absolutely no meaning (other than to yourself).
Secondly, tattoos using Hebrew script are deeply offensive to many Jews, especially the dark clothed, bearded
Hasidim... but others as well. (The detested tattoo applied to the forearm of prisnoers by the Nazis in death camps is still an all-too-fresh memory).
Thirdly,
Leviticus 19:28 prohibits the tattoing of ones body; so again a tattoo rendered in Hebrew script isn't going to impress anyone who may recognize it.
Lastly, the first part of your phrase "... I am who I am..." comes perllously close to the unspeakable name of God for the Hebrew... that being the tetragrammaton ;
Yodh He Waw He (YHWH in English). Traditionally, God identifies Himself, when Moses asks the burning bush "whom shall I say sent me?", as "I am that I am" (or alternatively, I will be Who I will be)....
As to script, however, the most appealing and attractive, at least to me is Aramaic:
http://www.ancientscripts.com/hebrew.htm, although the "crowned" script is equally pleasing to the eye:
http://www.hebrew4christians.com/Grammar/Unit_ One/Aleph-Bet/Nun/nun.html (scroll down).
Best of luck!