All people start off with a physical water birth and their bodies and minds eventually develop through physical puberty. But God also designed us to eventually experience a spiritual awakening, a “spirit puberty”, so that people can have the desire to want to notice when God attracts them into a relationship with Him (Acts 17:27, Ecclesiastes 3:11).
Prepubescent boys and girls may squabble with each other and not see the value of a relationship with each other, but at physical puberty their thinking starts to change. If they can avoid the temptation towards a false understanding of their own mind and body or the temptation to bond with their own biological gender, then they will start to see a new value in each other. But they don’t immediately forget all the animosity between them, they start off befriending each other and eventually picking a favorite to begin bonding with. But they will still on occasion fight with each other like they did before puberty. Over time as a pair they will grow closer and mature together as their values change and begin nesting and building a family and fight like children less often.
Spiritual puberty is similar, at some point a person will start to ponder the really big questions like “Why am I here”, “Is there a purpose to it all”, “Is there a god and what does that god want”, etc. If the person can avoid the temptation to pick a false god or permanently reject the idea of a god in favor of philosophy or science, or distract themselves with fantasies about spiritual life, they will choose the God of the Bible to begin a relationship with. But that doesn’t mean they immediately forget all the ideas about life they had before. They will start off with all the misconceptions and behaviors they developed before they met God. But now they have the chance to gain knowledge and wisdom from their Bible study and prayer and learn how God wants to steer their conscience through His Spirit dwelling within them. The bit of faith God gave them when He attracted them to begin with (“effectual calling”) will lead to a desire for more knowledge from Him. This develops God’s wisdom in them and a better understanding of what “believe” means. Gaining experience from obeying or ignoring what they have learned leads to knowing the importance of obeying what they believe. So over time they will struggle less with the character traits they had before they were saved.
Some people that have passed through physical puberty and avoided the temptation to choose an abberant lifestyle will attempt to form adult classical gender definition roles with each other but never start maturing into the single flesh idea of marriage that God intended. They either change partners on a whim or bond with a favorite but keep thinking and fighting like children the rest of their lives. There is a similar risk in spiritual puberty for many of the people that have chosen the God of the Bible but never properly committed to Him. They start off loving the basic milk of the word desirable ideas like Grace and forgiveness and having a golden ticket to Paradise for eternity, but they never develop the relationship that God wants to have with them now on this earth. They never learn from Bible study that God wants them to become a submissive student yoked with Jesus. Instead, they risk using their own imagination to create a “jesus” god that matches up to what they want, then find a local church or community that is compatible with that. Unfortunately this fake god may have some of the trappings of Christianity around it, but it has no power to provide a paradise in eternity and the guidance it offers now is corrupt and based on pride and pandering to peoples’ carnal desires. The end result of worshiping a fake jesus god of a person’s imagination is the same as that of any other unbeliever.
Only God knows the timeline that a person should be maturing with Him. Just like different babies learn to walk at different ages, Christians will start to mature from milk to meatier beliefs at different times in their life with Him. But there are NO exceptions to the requirement that God wants His followers to develop their relationship with Him here on earth. Just like a child cannot learn to ride a bike before they learn to walk, ALL followers of Christ must eventually start to mature along the path God sets for them (2 Peter 3:18). They can either recognize this and learn to hear His guidance through their conscience voluntarily (2 Timothy 3:16-17), or God will start to encourage them more strongly in ways that may seem unpleasant (Hebrews 12:6, John 15:1-2). He may withhold His favor from someone so they can see that they are lacking somehow, or He may passively allow or actively cause some hardship that strips them of their pride so they can see the truth about themselves.
A person that thinks or maybe shallowly believes they are part of God’s Church, but after years still never develops a more mature understanding of Him, should absolutely ask themselves if they really are part of the Elect or have fallen for a clever lie in their imagination (2 Corinthians 13:5). This can only be done in a humble moment where possibly shameful and embarrassing truths about a person’s misconceptions can be seen and accepted (Matthew 26:31-35,69-75, Luke 22:31-34,54-62). The setting aside of a person’s pride (focus on “self”) that occurs then allows the person to notice if God is calling them to a relationship with Him (Acts 2:36-41).