Montessori is a philosophy. The implementation of which is not regulated. You can get terrible schools that slap the name Montessori up on a sign with no adherence to the philosophy. You can get Montessori schools accredited by AMI which is the most snobby accrediting body and their schools are generally really good and well financed. St. Alcuin in Dallas and Community Montessori i. Georgetown are 2 I am familiar with. However, Montessori schools are definitely not for all children. I have had to listen to far too many Montessori discussions, wife holds 2 different grade level certifications in Montessori in addition to her Texas public teaching certificate and a Masters in early child education. One of my kids goes to AISD Gullett elementary even with our connection to Montessori. Public school is better suited for him. Have you thought about having your daughter skip an elementary grade if she needs the academic acceleration? I don’t see gifted and talented as being all that important until middle school. For reference I went through a magnet school program 25 years ago starting with 6th grade. With AP courses I started my freshman year at UT with like 3 credit hours short of being a sophomore. Still took me longer than normal to graduate.