Good luck! I bit my nails until I was 23 years old. I tried everything including that paint on stuff that tasted bad, but nothing stopped me. I even thought once that I'd get acrylic nails and they'd look so nice I wouldn't bite them. Wrong. After spending $45 on them I bit them all off that night.
It's a very tough habit to break, but if I can do it anybody can do it. My nails are nice and long now. :)
Stella - sweet, timid, elegant, lovely, lively, amazing
Luna - large, unattractive, naughty, adored