hmm, nice advice from ambertrichs.
in line with, if you cant be nice, dont say anything.
taking it further, if you cant be awesome to a person, dont say anything
(but personally, after a long day of crappy people (in person or not) just meeting a nice person, is awesome.)
about the girl, just picture yourself as an old man, does it suck more or less without her in the picture?
if it sucks more, you could go the long road.
just try to be in her life as a friend. you were shit to her. gotta become gold again.
unless she finds someone else and better, you should automatically avoid the friends zone.
over time, she might fall in love with you again.
i doubt you should push it.
but you could go a bit shorter road, convince her to go on a date with you and make it as good as you can.
but these are just thoughts, not necessarily whats right in your situation.
if there is love in your heart, go with that.