In Matthew 13:1o Jesus’ disciples ask him why he taught in parables. Jesus replied, ‘To you it has been given to know the secrets of the kingdom of heaven…’ (Mat. 13:11). Here Jesus is referring to his disciples, i.e. the people who followed him and learned from him: these people, his disciples, were the ones who were going to understand the parables.
At the end of Matthew’s Gospel, Jesus tells the apostles to go and ‘make disciples of all nations’ (Mat. 28:19) — other people, including ourselves, have become disciples of Jesus now. So, as Jesus’ disciples today — people who want to learn from Jesus and follow him — we can understand the parables, too.