Birthdays

using System;

class AgeAfter10Y
{
    static void Main()
    {
        string input;
        int ageYears, ageMonths, futureAge, monthsDiff, daysDiff;
        ageMonths = 0;
        DateTime currentYear, bdate;
        currentYear = DateTime.Now;
        Console.WriteLine("This program will precisely calculate your age in years after 10 years");
        Console.Write("Please enter your birthday in the format (dd-mm-yyyy): ");
        input = Console.ReadLine();
        bdate = Convert.ToDateTime(input);
        monthsDiff = currentYear.Month - bdate.Month;
        daysDiff = currentYear.Day - bdate.Day;
        ageYears = currentYear.Year - bdate.Year;
        //The next code will check if you've had your birthday this year or not and substract 1y from your age if you haven't.
        if (bdate.DayOfYear == DateTime.Now.DayOfYear)
        {
            Console.WriteLine("Happy Birthday!");
        }
        else if ((monthsDiff == 0 && daysDiff < 0) || (monthsDiff < 0))
        {
            ageYears = ageYears - 1;
            ageMonths = monthsDiff + 12;
        }
        else
        {
            ageYears = ageYears + 1;
        }
        futureAge = ageYears + 10;
        Console.WriteLine("Your age is now is {0} years and {1} months", ageYears, ageMonths);
        Console.WriteLine("Your age in 10 years will be {0} years and {1} months", futureAge, ageMonths);
        Console.WriteLine("Have a nice day!");

    }
}