I don't think I'd recommend JoJo in general as a first manga or first book in Japanese, but once you've read some graded readers or an easier manga, I would recommend it for beginners. JoJo, like most manga is pretty dialogue heavy. Part 1 (Phantom Blood aka this Part) does suffer more from large text exposition blocks than other JoJo Parts, but since it's a little less than 5 volumes, I think it's pretty easy to decide to if you want to reread them later, comb through them, or skip them altog
Bizarrely Good for Beginners
I don't think I'd recommend JoJo in general as a first manga or first book in Japanese, but once you've read some graded readers or an easier manga, I would recommend it for beginners. JoJo, like most manga is pretty dialogue heavy. Part 1 (Phantom Blood aka this Part) does suffer more from large text exposition blocks than other JoJo Parts, but since it's a little less than 5 volumes, I think it's pretty easy to decide to if you want to reread them later, comb through them, or skip them altog