Vintage 1960s Young Ladies Art School Smock Xs/S

This is a really interesting piece from the 60s. It seems to be a smock for an art student, possibly a gown for graduating. It has a cool A-line style with removable collar detail. Forest green. Sleeves are wide. This was probably for a child or young person. The neck is very small, but you could leave it open without the tie detail snapped on. Buttons down. Measurements flat in inches: bust 20, waist/hip 21, shoulders about 14, length 21, total circumference of the neck is only 11.5 inches