Well I am probably the only person on here that likes Jojo so I'll help you out.
Finish watching part 4, then if you REALLY want to read part 5 you can but the translation is shit. I know people hate when others skip parts, but part 5 is very standalone and, while good, doesn't add much to the plot of the series overall. The problem I had with it is that it the characters have no personality due to the translating it from Japanese to Italian to English. And they translated it in fucking comic sans. The anime adaptations are very close to the manga, only removing a few very minor things in order to fill the time slot. You're not missing anything by watching the anime. Part 5 is being retranslated very slowly, so if you can avoid spoilers, I would go back and read it later.
That was a rant.