Ty explained his reasoning to Lyn. That he was cautious about changing his own form or self, as much as she reassured him that such changes should be totally safe to try, and having a legal guardian around, or at least what seemed like it being a young adult woman, would make less of the people who saw them skipping school find it worrying, without Ty needing to change anyone to get them ignoring him in public.
"Do you also prefer my more mature form as it is more pleasing to you, Ty?" Lynn also asked, with her hands reaching up to jostle her larger, fuller breasts in her twenty-something appearance. Ty felt his cheek begin to turn a little red, though he didn't bother to resist looking at the motion of a pair of large breasts being handled for his sake.
"Well, ah, that..." Ty stammered. "I'm actually an ass man, personally." It was technically true. Ty preferred to stare at the large, plump ass of his English Literature professor, Mrs Goldman, when she turned her back on the class, rather than the ogling his classmates often seemed to do at those large breasts she also had, but even so, Ty was a very enthusiastic fan of breasts, too.
"Oh." Lynn seemed unshaken by that news. She reached out with both hands, and touched both sides of her hips, and Ty became aware, all of a sudden, that those hips were now not the slender hips he had been sure that they were, but rather wide, bulging things, that filled out into thunder thighs and rounded out into a bulging blubbery bubble butt. "Thank you for the valued input."
"Ye- You're welcome..." Ty trailed off, distracted even more than before. After a minute or two, it had dragged on long enough that he felt shamed, but Lynn still held her placid expression of mild serenity and acceptance. "We- We should- I mean no, we should go."
"Yes, Ty. Your powers are to be tested outside of your home, first. In order to 'not shit where you eat', yes?"