I’m in my 20s and an active member in my church. I am a Seventh-Day Adventist (which is a Protestant/evangelical denomination) and was baptised in my teens, which is how you become an ‘official’ member to put it this way.
My current church is young, multi-cultural and very international - as is the city I live in (I’m white European for reference) - with most members between the ages of 15 and 40. This is the current trend in most countries around the world, it’s a growing young church. although you do find ageing congregations in smaller rural communities. In my local church we have many young families, and every week the babies and children have their own ‘classes’ alongside the main study session for the adults. Everybody worships together during the main service.
I have two masters’ degrees and I’m an intelligent person working in a competitive industry. Some of my friends at church are working for the UN, as lawyers, journalists, nurses, doctors and/or studying a range of subjects.
Like PPs have said, it’s easier to know other young Christians if you already are one. Some of these people at my church I would call good friends, others are just acquaintances, but it does feel like a big family. With friends we try to meet up once a month or so for dinner, cinema or to do sports or go for walks in the summer. Hasn’t happened since Covid but once a year we’d also go for a weekend away all together - hiking or to the beach for example.
I was always encouraged by my own parents to challenge what I heard in church and research and decide for myself what I wanted to believe in. I’ve gone and still go through phases of doubting my beliefs or not understanding certain things. I have always been very privileged to be a member of open-minded churches who encourage discussion and don't judge you when you question certain doctrines or interpret them differently (the vast majority of people don’t judge, like everywhere else there is also the judgy type present). This is sadly not the case everywhere, in all denominations… it can be hard to find a community where you can fit in just as you are.