Yep. Certified non-tech nerd here. And not quite 30, either.
I was awfully close to not figuring out Lemmy enough to make an account and participate.
I still don’t understand exactly what’s going on, but I can confirm that my first time visiting was extremely confusing. So many terms I was completely unfamiliar with, and no clear way for me to jump in easily (like you were describing with having to make important decisions before signing up/understanding). Truly the only reason I ended up successfully making it here was that I saw a post on the instance I ended up joining, welcoming reddit refugees so I figured - well, I guess I could try this one. And that was after I had searched around online to figure out what the heck the fediverse, instances, etc, were.
The barrier to entry is really high for those of us with little to no tech knowledge. And I was really motivated, I reeeeally wanted to commit to leaving reddit. I imagine those who are considering joining but aren’t quite as motivated just won’t make it. :(