I actually agree with andycarmenjapanese8100-san.
If you don't have problems (or even better if you enjoy) watchin children's shows, those TV programmes and
books are really helpful. They don't use difficult words, they inunciate, they might speak slowly, etc.
In fact, my best material for studying English was Sesame Street
It's difficult to tell which manga/anime would be the best for beginner learners. They usually use quite specific
words and ways of speaking (generally speaking colloquial, casual, and those expressions that we might actually
not use in daily life). This applies to both manga and anime (comic books and catoons)
It's totally okay to use those resources if you don't get confused or learn wrongly; the worst
would be you get shocked and discouraged.
I was wondering if you watch/watched manga/anime in your own language? If you find them both in your language
and Japanese, it might be the best, because you can compare them to understand.
It's not too early to start, but just know that language used in manga, anime, and any TV dramas is very different.
Hope you can use those materials very wisely; if you do, they're the best materials, right?