Help me calculate avg

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Practical_1_Q16_Calculate_Average
{
    class Program
    {
        static void Main(string[] args)
        {
            double total = 0;
            int count = 0;
            double score = 5;

            Console.WriteLine("Enter a score (0-100): ");
            score = double.Parse(Console.ReadLine());
            while (score < 0 || score > 100)
            {
                Console.WriteLine("Invalid, must be 0-100");
                score = double.Parse(Console.ReadLine());
                total += score;
                count++;
            }
            if (count == 0)
            {
                Console.WriteLine("No numbers were entered.");
            }
            else
            {
                Console.WriteLine("Average:" + total / count);
            }
            Console.WriteLine("");
            Console.WriteLine("Program finished");
            Console.ReadLine();
        }
    }
}