To check if your school is a TRUE MONTESSORI ask then to show their accreditation/affiliation through American Montessori Society (AMS) or AMI (Association Montessori International) or MACTE .

Montessori preschool Classroom Traditional(Child care, daycare,preschool) Classroom
Prepared kinesthetic materials with incorporated control of error, specially developed reference materials Textbooks, pencil and paper, worksheets and dittos
Working and learning matched to the social development of the child Working and learning without emphasis on social development
Unified, internationally developed curriculum Narrow, unit-driven curriculum
Integrated subjects and learning based on developmental psychology Individual subjects
Uninterrupted work cycles Block time, period lessons
Multi-age classrooms Single-graded classrooms
Students active, talking, with periods of spontaneous quiet, freedom to move Students passive, quiet, in desks
School meets needs of students Students fit mold of school
Special help comes to students Students leave for special help
Process-focused assessment, skills checklists, mastery benchmarks Product-focused report cards

From the Montessori Foundation,