Validation.Validator.CheckDate C# (CSharp) Method

        public static bool CheckDate(string day, string month, string year)
        {
            const string monthPattern = @"(1[0-2]|0[1-9]|\d)";
            const string yearPattern = @"(19|2[0-1])\d{2}$";
            const string dayPattern = @"[0-9]";

            return IsCorrectFieldData(month, monthPattern)
                && IsCorrectFieldData(year, yearPattern)
                && IsCorrectFieldData(day, dayPattern);
        }