The Fenton family lives above a literal hole in reality. Can we just- talk about that please? Like maybe Maddie and Jack aren't affected as ... (badly?) Jazz or Danny but like. Their fixation on ghosts and stuff- I just feel like that could've been exacerbated by all the ectoplasm and being in such close proximity to the portal.
I imagine that the Fentons moved in like two years before Danny was born, so when Jazz was a tiny baby. She wasn't born in Amity Park, but she grew up in one of the thinnest areas between Earth and the GZ. Maybe that's why she's a bit more openminded about stuff? Idk it's been a bit.
I think that Danny and Jazz would've been somewhat weird as tiny kids, and it got more noticeable in middle school (they were jokingly called the "cryptids"), and then suddenly bam. They hit highschool and suddenly the only weird thing was their parents and stuff.