extension Date {
    var age: Int {
        return Calendar.current.dateComponents([.year], from: self, to: Date()).year!
    }
}

extension DateFormatter {
    static func getDateFormatter() -> DateFormatter {
        let df =  DateFormatter()
        df.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.sssZ"

        return df
    }
}

let dob = "1993-10-14T00:00:00.000Z"

let date = DateFormatter.getDateFormatter().date(from: dob)

let calendar = Calendar.current
let components = calendar.dateComponents([.year, .month, .day], from: date!)

let myDOB = calendar.date(from: DateComponents(year: components.year, month: components.month, day: components.day))!

let myAge = myDOB.age      // 25