My daughter stopped when she got 31 on the ACT. I wish she had tried one more time but given where she started (27), I understood her fatigue. If you can convince your daughter to study and take the ACT one last time, more power to you. More scholarships open to students at 3.5 GPA and 32 ACT.
FWIW, my daughter matured a lot academically get senior year. Her best grades ever actually came second semester senior year. So even though your daughter may still have some areas of improvement, she may improve there next year before she his college.
Do some early action or rolling admissions in the fall to the schools where her 31 ACT is well above the 75th percentile. (Kansas? Bowling Green? Ohio Wesleyan? the Wisconsin schools?) Some schools that say Early Action are somewhat like rolling in that they will give you a decision within a certain time after submitting an application.