I love Maya. My second pick would be Mara, followed by Margo.
1.) Margot: love this one, though I do prefer the French spelling Margaux
2.) Marlene: Very elegant and beautiful but I prefer it pronounced Mar-lay-na a la Marlene Dietrich.
3.) Mara: Sweet, simple and very lovely.
4.) Mariah: Very pretty, though it will be forever tied to Mariah Carey (which can be good or bad, depending upon your viewpoint).
5.) Maya: really overused and boring to me, definitely not my style.
6.) Marlowe: Sorry, but I really, really dislike this one...ick.
I would pick Maya. Mara has an awful meaning. It means bitter. I have a childhood friend named Mara who completely fits that meaning and I always think of "bitter" when I see/hear Mara. Margot is nice, too.
Definitely Maya or Marlowe
Marlene is too dated since your around my age (15 isn't it?) it could be ok by then