My daughter is 17 and she's struggled with school,...

My daughter is 17 and she's struggled with school, mainly math her entire life. She attended a middle school in Lake County where she was held back in 7th grade 3 times due to the math FCAT testing. She's in 8th grade now doing FLVS and I've seen much improvement, but she wants to go back to public school. I contacted school board and asked them if she could even go back being 17 in the 8th grade and they said she'd only be able to attend boarding school. Is this true? Are there any other options? If so, please help.