Everyone functions by beliefs (whether in Christianity or another system). What we believe to be true, beautiful, and good are the most profoundly shaping things in our lives.
In my short stint on planet earth, I've come to see some recurring patterns in various life stages that I'd like to point out. Various ages are prone to different characteristics. On one hand, these characteristics are not "good" or "bad," but their extreme forms are dangerous. I've specified age ranges for the sake of simplicity, but since every human is unique, we should allow for great variation.
Here's a simple taxonomy:
Children ages 0-11 usually take on the beliefs of their parents--especially parents who are loving, emotionally stable, and involved. If their parents function reasonably well, the children assume they are to function similarly. If the home of origin is broken or painful, children will run to the arms of anyone who cares or find any and all ways to escape through media, rebellion, relationships, etc.
Youth aged 12-16 begin to take on their own belief system. It's primarily shaped by those who engage with them in a loving and supportive way (parents, friends, teachers, coaches). The 7th grader who finds his liberal history teacher friendly is most likely to be open to liberal ideas. The 9th grader who finds acceptance at their school's Christian ministry will be apt to take on Christian beliefs.
Students 17-23 begin to see the world as black and white. There are people who are right and wrong. There are good ideas and bad ideas. Sometimes people cut off relationships with family and friends because they cannot reconcile different beliefs and relationships. (Interestingly in the past 50 years or so, the dominant black-white ideology of US culture is that no one should judge another person. This is held with white-knuckle conviction and other people are judged for thinking otherwise [catch the irony?].)
Young adults 24-30 begin to feel guilt for their black and white days. They meet nice people with extremely different beliefs and practices. The categories that seemed to work a few years ago don't line up as simply as they did before. The danger at this point is to quit believing some ideas are right or wrong entirely. We become tolerant of too much and quit thinking hard about how beliefs ultimately shape people. These final years before children and increased responsibilities end up setting a trajectory for many many years.
Adults 30-50 do not have much time to reconsider beliefs. They had two decades from ages 10-30 to work out their ideas, but now they have jobs, kids, bills, and the like. If a major life event occurs, they might pause and rethink their beliefs, but normal day-to-day living (with hours of Netflix binging not helping) keeps them from slowing down to evaluate their cherished beliefs.
Adults 50-65 slow down enough to set a fresh course of living. No longer are their kids watching (so they think). Previously faithful Christians start looking more like 20 something socialites. Formerly committed non-Christians seek solace in the church. It's an interesting time. What I've found is that these years are too often wasted. Instead of stepping into the role of mentors and coaches for those younger, these "empty-nesters" choose to take more vacations, drop their volunteer responsibilities, and fade out of the church.
Adults 65-death cherish their beliefs. They believe those beliefs have brought them to where they are today and so they are confident that this is the way all others should go. This leads to anything from old curmudgeons or kind evangelists of worthy causes. Sadly, the younger generations don't look to these wizened souls.