To be very frank... you shouldn't. My collegue /u/commiespaceinvader has a really great piece on this which I would echo and build off from slightly. To be clear, Mein Kampf is a primary source document that one must eventually engage with when studying Hitler, but it really is not your first stop, nor your second or third stop. It is more your very optional 15th stop after you've read a really solid biography or two (Ian Kershaw's duology is a good one to pick up), some general histories of the Third Reich (Richard Evans' trilogy is the 'go to' recommendation), and some more specialized works that really dig into the the topic of Nazism, like Tooze's "Wages of Destruction" or perhaps Rees' "The Holocaust".

The simple fact is that primary source documents are, for the most part terrible ways to start learning about a topic. Understanding them in the context of their importance requires a decent amount of background knowledge and understanding to get any sort of value. This is doubly true for a book like Mein Kampf which isn't only terrible in terms of the content, but by common agreement is actually just a terrible piece of nearly unreadable prose. You say that you are concerned about "judging it without taking context into account", well, what that means is that you need to learn the context of the book first. Once you feel you have a decent grasp on the topic, well, read Mein Kampf if you must, but really, you can get by well enough with excerpts as it is a lot of drivel to wade through, for incredibly little payout.