According to all Yamato fans, she didn't read the most important parts. She just skipped them for the purpose of joining Luffy.
as a Yamato fan, I’ve already explained it before. If you haven’t read, let me mention again:
it’s illogical for Oden, a Poneglyph writer & reader, to put many very important informations in just scrap of papers (ie: One Piece, Laugh Tale, will of D, void century, etc) with normal language (I suggest normal language since Yamato & Momo can read it; unless Yamato & Momo are poneglyph readers too) where everybody will be looking for it for their own personal purpose.
The reasons it’s impossible to write things like Will of D, Laugh Tale, Void Century, etc. are:
1. it can be destroyed easily. CP0 would have chased Yamato, probably ambush her & take the journal to destroy it / to take it to World Govt for their own purpose. It’s good if it’s destroyed, hence further makes Yamato’s chance to be on crew pretty much higher. Luffy could’ve just asked Yamato not to mention anything about Laugh Tale, etc. although I highly doubt if it ever mentioned anything about Laugh Tale, etc. but if it does and it’s being taken to World Govt, that’s very dangerous. World Govt could take it, get the information about Laugh Tale, and destroy it.
2. It does include information like Joy Boy; hence suggesting why Kaido & Yamato knows about Luffy being a Joy Boy while so far, only Robin knows about Joy Boy. Kaido may have already read that journal also; hence his knowledge of Joy Boy. But I think the important message is only that (or maybe more), but would NEVER include other very important informations, as if it would, Kaido would have been aiming for Laugh Tale ages ago. It would also destroy the purpose of Kaido having Road Poneglyph. He would have just taken Oden’s journal and go straight to Laugh Tale. And thus this point emphasizes point 3.
3. If it did contain Laugh Tale, One Piece, etc. it would have destroyed the purpose of Poneglyph. Back again; Oden is a Poneglyph writer & reader. Robin is currently the only person who can read & translate Poneglyph; hence great pirates are all looking for her.
so the biggest question is: why Oden, a Poneglyph writer & reader, would want to put very important things like Laugh Tale, One Piece, etc. in scrap of papers with normal language where it can be destroyed / it can fall into wrong hands?
hope my explanation helps