Amanda Bynes -- Life After Rehab -- Enrolls In Fashion School

Amanda Bynes is wasting no time trying to rebuild her life after rehab ... and plans to hit the books at a private design school because she wants to become a fashion designer, TMZ has learned.

Sources close to Amanda tell us she's enrolled as a student at FIDM -- the Fashion Institute of Design and Merchandising -- registering under an alias for 2 classes at the Orange County campus.

As we reported ... Amanda was sprung from rehab in Malibu last week and released to her parents' care. She was being treated for bipolar disorder and schizophrenia.

We're told ... the people close to Amanda believe school will help ease her back into society by giving her some sort of structure for her life. She's taking a light class load -- by design -- and will be escorted to and from her classes.

We're also told ... the treatment that began in rehab will continue during the school year ... Amanda will juggle her classes with 4-times-a-week therapy sessions.