Did I mention that you and Taira go to the same high school? Just go with it. There is no explanation as to why a T-rex attends a human school, much like how there's no explanation as to how he managed to tie his necktie (the only item of clothing he wears) with such stubby arms.
If you play your cards right, you and Taira leave the music store with a new ukulele, and Taira invites you to go to the park with him. He's a little shy, but after a while he explains that he has some self esteem issues. Back in middle school he dropped his first ukulele halfway through a concert, and people laughed at him because he couldn't pick it up.
Current Music: Fortran 5 -- Two Curious Friends ♬