Import CSV in metabase as a model


I used the CSV import feature.
The CSV I imported is rather simple, the columns are :
date (DD/MM/YY) / number / number

When I import the CSV, i need to have the date column recognized as dates. I use the formatting feature.
My issue is that not the whole values in the column date is recognized as a date (even if the format is homogeneus), and i cant aggregate data by month or whatever.

Thank you in advance