Why was Leo surprised when he saw Stargirl's house, particularly her bedroom?

When Leo
goes to 's house to meet her parents, he's surprised to find that they're so incredibly normal.
Given Stargirl's many strange quirks, he'd expected them to be every bit as wacky as their dippy
daughter. But it would seem that, in Stargirl's case, the apple fell some considerable distance
from the tree.

If Leo is astonished at how normal Stargirl's parents are,
he's even more flummoxed by the normality of her bedroom. This, after all, is her inner sanctum,
the place where you'd expect her to give free reign to her quirky personality. And yet it's all
so conventional, with nothing out of the ordinary.

Nevertheless, there's
always something interesting about Stargirl, and her bedroom is no exception. As Leo explores
the bedroom a couple of interesting objects capture his attention. First of all, there's a bowl
of hair. Like most people, Leo finds this all rather icky, if fascinating in a weird kind of
way. But for Stargirl this is her way of giving something back to the natural world which she
adores, and with which she has such a close affinity. For the hair in the bowl is freely
available for birds to use as nesting material.

The second object is a tiny
wagon full of pebbles. Whenever Stargirl's feeling happy, she adds a pebble to the wagon. And
whenever she's feeling a little blue, she removes one. So the little wagon with the pebbles acts
as a kind of barometer for Stargirl's mood. Leo notices that there are seventeen stones in the
wagon, a clear indication that Stargirl's very happy with her life.