According to the documentation of the Read method:
Reads the next character from the standard input stream.
So this will returns the ASCII value of a single character that the user entered.
You need to read the entire line and parse the string back to an integer:
int num;
Console.WriteLine("Please input age: ");
num = int.Parse(Console.ReadLine());
Console.WriteLine(num);
of course this parsing might fail if the user enters an invalid integer. So you could handle it like this:
int num;
Console.WriteLine("Please input age: ");
if (!int.TryParse(Console.ReadLine(), out num))
{
Console.WriteLine("Please enter a valid age");
}
else
{
Console.WriteLine(num);
}