Peter's friends are going to a party that serves alcohol, but peter refuses to go because he is 15 years old and is below the legal drinking age in his country. peter knows that he will not get caught but strongly feels that it is important to not do something that is illegal. in the context of kohlberg's stages of moral development, peter is at the of moral development in this scenario.

Peter is at the conventional stage of moral development. 

The conventional stage of moral development involves internalizing the norms and moral values of society by obeying the law and authority figures. Peter seems to be at the fourth stage of Kohlberg's theory moral development, known as "Maintaining Social Order". In this stage, individuals make moral judgements and decisions in order to obey and comply with official laws and rules of society.