[{"etd":"15-Mar-21",name:"Name 1"},{"etd":"10-Mar-21",name:"name 2"},{"etd":"20-Mar-21",name:"name 3"},{"etd":"19-Mar-21",name:"name 4"}]

db.collection.aggregate([{$addFields:{date:{$dateFromString:{dateString:"$etd"}}}},{$match:{date:{$gt:ISODate("2021-03-15T00:00:00Z")}}}])