People tell me that since I'm a 15 I can't evangelize, be concerned about salvation, or have meaningful spiritual relationships. I can't wrap my head around the idea that the whole Bible is just for adults and your life doesn't mean anything until you turn 18.
You’re completely right to struggle with the idea that there’s such things as “kids' Christianity” and “adult Christianity” because this is a false belief. There are no second-class believers. There are no minor leagues for faith. Faithful service and spiritual wisdom does not require reaching a certain age. While some aspects of Christian living take time to develop, those aspects grow and mature at different rates for different people, and they don’t prevent a person from following God's commands.
No matter what your age, there is no reason you cannot evangelize or develop trusting relationships with other believers. You can still deeply study Scripture. You can still choose to commit to serving and honoring God with your life. None of those are meant to be put off until you’re a certain age. They’re vital aspects of faith and our relationship to God. Even figures in the Bible struggled with that problem; Paul told Timothy not to let people discourage him due to being relatively young—that he still had much to offer others (1 Timothy 4:12).
That said, it's important to remember that age and experience DO have value. Some believers have been preaching and evangelizing longer than you’ve been alive. That means you can and should learn from the godly examples available to you (Hebrews 13:7). They likely know things that would never occur to you at this stage in life. That doesn't negate your experience; rather, it provides an opportunity to enhance your own wisdom.
Relationships are much the same. There’s a reason we’re meant to save lifelong concepts like sex and commitment until we’re fully capable of wielding them. Younger people—or newer believers—should not ignore the need to grow into some of their spiritual strengths (2 Thessalonians 1:3) before pursuing a lifelong commitment to a romantic partner.
Ultimately, a Christian teen’s spiritual life doesn't need to look that drastically different from that of a Christian adult's life. Of course, not every single aspect will be the same as responsibilities and priorities will differ depending on our stages of life. Young Christians would do better to wait before jumping straight into "adult life" things. But no part of our spiritual life—prayer, study, evangelism, worship, service, giving, etc.—needs to wait or is reserved for only grown-ups.
Younger believers can think about deep topics and accomplish great tasks. God can use a young believer just as powerfully as He can use an elderly believer. Relying on the advice and support of more experienced Christians is important (Proverbs 19:20), but there is no reason for any genuinely believer to sit around waiting to engage in their own faith.
Jeff is a staff writer with Got Questions Ministries and used to be a mechanical engineer. When he's not accidentally setting things on fire in his workshop, or petting strange dogs, he loves helping people better understand God’s Word and how it applies to our lives. Jeff's calling is to untangle the "big picture" of Christian faith, making it easier to understand.