feat: display car age

CarManagerV3/CarDetailsForm.cs

@@ -25,6 +25,7 @@ namespace CarManagerV3
             tbxColor.Text = car.Color;
             nudMileage.Value = car.Mileage;
             nudPrice.Value = car.Price;
+            tbxAge.Text = car.AgeString;
             pbxCarImage.Image = ImageManager.GetImage(car);
             lblID.Text = $"ID: {car.Id}";
         }
@@ -79,9 +80,12 @@ namespace CarManagerV3
 
         private void nudYear_ValueChanged(object sender, EventArgs e)
         {
-            Console.WriteLine("Year value changed: " + nudYear.Value);
             SafeUpdate(
-                () => car.Year = (int)ValueOrFormer(nudYear.Value, car.Year),
+                () =>
+                {
+                    car.Year = (int)ValueOrFormer(nudYear.Value, car.Year);
+                    tbxAge.Text = car.AgeString;
+                },
                 () => nudYear.Value = car.Year
             );
         }