[watwut]

I think that 1. is very bad idea and so is 2.

Both means that if the book you picked assumes you already knew something you don't really, you are stucked. If your book happen too explain something later or is not perfectly written, you are set up to fail.

Very often, later concept let's you figure out the first one. Very often, another book or source adds details to have been missing. Very often, you need to do something else for a while and when you come back to chapter, it suddenly clicks.