[{"_id":"KPu78LNXYKfraRF94","aboutPage":{"birthDay":NumberInt(27),"birthMonth":NumberInt(5)}},{"_id":"shouldReturn","aboutPage":{"birthDay":NumberInt(18),"birthMonth":NumberInt(11)}},{"_id":"2daysbefore","aboutPage":{"birthDay":NumberInt(15),"birthMonth":NumberInt(11)}},{"_id":"3daysbefore","aboutPage":{"birthDay":NumberInt(14),"birthMonth":NumberInt(11)}},{"_id":"today","aboutPage":{"birthDay":NumberInt(17),"birthMonth":NumberInt(11)}}]

db.collection.aggregate([{$set:{birthDate:{"$dateFromParts":{"year":{"$year":"$$NOW"},"month":"$aboutPage.birthMonth","day":"$aboutPage.birthDay"}}}},{"$set":{"daysFromToday":{"$dateDiff":{startDate:"$birthDate",endDate:"$$NOW",unit:"day"}}}},{"$match":{daysFromToday:{$gte:-1,$lt:3}}},{"$unset":["daysFromToday","birthDate"]}])