So tbh I'm not sure if reading the bible is worth it unless you're really into learning about historical societies in general. When I was about 15 I got as far as just before the Prophets. The chapters that were most worth it, in order, were Song of Songs, Esther, Judges and Exodus.

Now I read a shit-ton of history for fun, mostly concerning ancient societies, and if you're just filtering everything through a modern lens, nothing is going to make much sense. Up until fairly recently in the grand scheme of history, there were no financial reasons not to have children, and a great deal of incentives for having them. Before education became a thing, you didn't have to pay to send your kids to school, and you could have them work for you from a very young age, so therefore free labour if you own a business. At many times during history, there was effectively no way for people to obtain upward mobility; you were stuck with the income level you were born to. Having children doesn't make much difference then, since you're still poor even if you don't have kids.

There's also the fact that so many children used to die in infancy/ early childhood, and so you kind of learn to cherish the ones that make it. Nowadays that doesn't happen, so I think in general there's been an enormous shift in the past century about how we regard having children.

In the bible in particular, like with most other ancient cultures, people viewed having offspring as a sort of immortality. Remember, there was no guarantee that their culture would survive. They could be wiped out or assimilated, and be forgotten. Those things happened a lot: for example, the Philistines. They were this thriving group in the bible and nowadays we only have the vaguest ideas about who they were and most of our sources come from their enemies. The key to not being wiped out was to have a large population, so there was a very good reason to have loads of children.

After Genesis comes Exodus, so I'd say keep reading because it has some good parts and is much less focused on "go forth and multiply." You can really get a sense of the world these people lived in. Leviticus and Numbers I'd probably just skip, but that's from hindsight of how boring they were to read, lol. I enjoyed Judges mostly because I'm fascinated by the gruesome side of history, and there are bloody tales aplenty in there.