I would definitely vouch for a beginner box of Starfinder. I had the core rulebook for Pathfinder and was very bogged down by all the details and didn't know where to start (being a very new GM and player) - and then came the Beginner's box and all was clear and fun and quick to start.
Is there a beginner's introduction of some sort in the Starfinder Core Rulebook? Is that why you're hoping that you won't need a beginner's box? I'm honestly curious about this, I haven't had the chance of checking out Starfinder yet.