Don't worry. You are correct, if you put the egg(s) in the fridge they will not grow, they need heat. If you would want chicks I suggest getting an incubator. You could also leave the eggs for your hens to sit on. To tell if an egg is fertilized you can do something called, "candling". On day 4...
I can usually tell by cracking eggs open to eat. In fertilized eggs, you will see a white spot known as, "blastoderm." You may even see some blood, like I do. It is perfectly safe to eat fertilized eggs. Here's a picture of a fertilized egg: