yea you do. like, all the conjugations of verbs, nouns, adjectives, etc. are done in hiragana. besides, ud need it to differentiate kanji meanings with furigana.
also, its not hirIgana, but hirAgana. mkay? also, if u learn katakana and the basic way to adapt engrish words to jap, u already know a bunch of words, just be careful with fake cognates.