We some times do few mistakes with or without intention. If it is without intention, people might leave it, but if it's done with intention, then the circumstances of it might be severe.
In those situations, generally we try to apply masala to the mistake done while giving the explanation. In the process of it, we might try to convince the opposite person, but that does not convince, but confuses sometimes.
When the opposite person feel that he is getting confused, he takes it granted that you are lying him. Then he might take any serious action. Instead of creating all this, just accept the truth that you committed mistake and explain what are the situations that made you to commit.
Now, opposite person gets a clarity and his mind comes to your control. Now, you start convincing him that you did it just out of your immaturity. Remember, that the faults committed out of immaturity would make people think positive about you and creates a type of sympathy too. So do not miss this logic when you face the apt situation.