I don't particularly agree with that, a weeb generally means someone who is (unhealthily) obsessed with japanese culture. It was originally used as an insult to people who behaved unusually due to their obsession with japanese stuff (often anime).
From my understanding otaku is a more broad thing and refers to people who are especially interested in certain topics, commonly anime. But you can technically be an otaku for various topics... However nowadays it's often safe to assume if it's used in a western setting that it's someone who is particularly interested in anime.
If you were to be literal, then a weeb should be like... noticeably into anime/japanese stuff based on their behavior. If you're not particularly obsessed with anime or similar stuff, I wouldn't really classify you as a weeb by the technical definition. I wouldn't question using it in a less serious/joking fashion, though.