When he was four or five, Mi-chan was a lot smaller. She's only just about football sized, maybe a bit bigger now, so at least... she would've been smaller if she did decide to say hello to Hinata back then? Most Shizuoka tend to be more secretive regarding their spiders and discrete with them for the simple fact that the clan doesn't want shinobi with a grudge going as far back as the warring states period to catch onto the fact that lolol that clan that did X that we hate and would love to break is actually still around under another name and, you know, cause Konoha issues and complicate them doing things, but Masanori tends to break the mold.

That said, Masanori is currently twelve, turning thirteen in July iirc! He was probably a bit shy about Mi-chan save in Shizuoka and Uchiha company around four since that's the age he first got her, but that would've rapidly gone out the window degree by degree as those two got closer. He's not so much LOOK AT MY SPIDER as he is just very, very comfortable and close with her and she with him in turn, so they just p. much are together most of the time or close. [insert that You and Me and Me and You song here]

If they met when Masanori was five and he got the idea that Hinata was scared of spiders, he might've kept Mi-chan under wraps and just offered to be her spider exterminator and just spirited spiders away from her forever? Spiders are great, Hinata. Why you do this. And bless her if she never meets his jiisan that old man is the creepiest spider of them all.

Welp, I vote we toss him at everyone and see how things go! Masa'd probably peer at Temari because diplomat and maybe establishing some relation there could be useful in the future! As for Karin, she's an Uzumaki from that recently established village and that screams interesting to him. He wants to ask all the questions! \o/