Opinionated
Part of speech: adjective
Definition: Holding to one's own opinion, obstinately, stubbornly and unreasonably.
Example sentence: I am a very opinionated person and I have stuff that I believe in. But I've always struggled to find my niche amidst it all.
Narrow-minded
Part of speech: adjective
Definition: having restricted or rigid views, and being unreceptive to new ideasintolerant, bigoted or prejudiced