Would you still read the Ainulindalë and Valaquenta first, or would you save those for last?

I would also add that the chapter "Of Beleriand and its Realms" is OK to skip if it's not your thing, especially on a first read. It's mostly just describing what's on the map (of course it's still well written in Tolkien's prose). There are plenty of people that enjoy it, and there are plenty that don't.