shelley dufresnein of st charles parish , louisiana , took a plea deal .
mother-of-three avoided prison and wo n't have to register as a sex offender .
took an image of her smiling after the hearing and wrote : ` my mood today '
also said she was ` relieved ' when followers began congratulating her .
is still facing charges over an alleged threesome she had with the same student and fellow teacher rachel respess , 24 .