It will take at least as long as it will take for you to realize that this question is unanswerable. A mature Christian is one who exercises godly wisdom and does not become disillusioned by the things that people do, but, rather, stays focused on Christ.
A mature Christian is one who realizes the vast amounts that he does not yet know. Many people develop spiritual pride and think they know more than the average Christ-follower. These people are not mature! This old saying is very true in Christianity: The more you know, the more you know you don’t know!
A Christian who realizes the truth about his or her own knowledge, who seeks the counsel of the Holy Spirit before jumping into action, and who consults the Bible for truths about Christianity, is most likely a mature Christian.
So, becoming a mature Christian can be easy or it can be very difficult. How willing are you to surrender yourself, fully, to the molding process of the Holy Spirit? Maturing, refining, shaping, and molding are all painful processes. But, always, the end result is more beautiful than could ever be imagined.
Colossians 1:21-23 And you, who once were alienated and enemies in your mind by wicked works, yet now He has reconciled in the body of His flesh through death, to present you holy, and blameless, and above reproach in His sight— if indeed you continue in the faith, grounded and steadfast, and are not moved away from the hope of the gospel which you heard, which was preached to every creature under heaven, of which I, Paul, became a minister. (Jesus does the work)
Philippians 1:6 Being confident of this very thing, that He who has begun a good work in you will complete it until the day of Jesus Christ;
Colossians 1:28 [Christ] Him we preach, warning every man and teaching every man in all wisdom, that we may present every man perfect in Christ Jesus. (maturity through listening to the Word in a Bible believing fellowship – hopefully without having to be pressed through the grinder of life to cement the lesson)
James 1:3-5 Knowing that the testing of your faith produces patience. But let patience have its perfect work, that you may be perfect and complete, lacking nothing. 5 If any of you lacks wisdom, let him ask of God, who gives to all liberally and without reproach, and it will be given to him. (maturity through circumstances)
Philippians 2:14-15 Do all things without complaining and disputing, that you may become blameless and harmless, children of God without fault in the midst of a crooked and perverse generation, among whom you shine as lights in the world... (more maturity through circumstance, with the added discipline of not whining)
Philippians 4:12-16 I know how to be abased, and I know how to abound. Everywhere and in all things I have learned both to be full and to be hungry, both to abound and to suffer need. I can do all things through Christ who strengthens me. Nevertheless you have done well that you shared in my distress. Now you Philippians know also that in the beginning of the gospel, when I departed from Macedonia, no church shared with me concerning giving and receiving but you only. For even in Thessalonica you sent aid once and again for my necessities. (what spiritual maturity looks like after having life kick the stuffing out of you)
Ephesians 4:11-15 And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ; that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head—Christ— (the glorious truth that we are called to participate in helping Christ bring ourselves and others into spiritual maturity).
From Rapture Ready: http://www.raptureready.com/faq/faq24.html
Fair use for educational and discussion purposes ~
“You will be like the wings of a dove covered with silver, And her feathers with yellow gold.” — Psalm 68:13
“O that I had wings like a dove then I would fly away and be at rest.”