A good indication whether we are mature in Christ is our orientation to the upward-call. The upward-call is the life orientation towards living for and meeting our Lord. Maturity does not come from logging in numerous years as a Christian. There are Christians who have known Christ for many years and they are still spiritual babies. It is possible to register substantial time in the Christian life and it does not mean a thing except that person is getting old.
Many people offend easily.
They wear their feelings on their sleeves. This person is obviously still a baby. They do not understand the principles of God's Word nor how to apply them. Maturity is maximum application of truth to experience. If we apply God's truth regularly to our sin and failure, we will grow.