What is Sal comparing herself to in the first few paragraphs of the novel when describing her move from Bybanks to Euclid in the story "Walk Two Moons"? (The First Chapter)

Gramps says that I am a country girl at heart, and that is true. I have lived
most of my thirteen years in Bybanks, Kentucky, which is not much more
than a caboodle of houses roosting in a green spot alongside the Ohio River.
Just over a year ago, my father plucked me up like a weed and took me and
all our belongings (no, that is not true - he did not bring the chestnut tree or
the willow or the maple or the hayloft or the swimming hole or any of those
things which belong to me) and we drove three hundred miles straight north
and stopped in front of a house in Euclid, Ohio.
'Where are the trees?' I said. 'This is where we're going to live?'
'No,' my father said. 'This is Margaret's house.'
The front door of the house opened, and Margaret, the lady with the wild
red hair, stood there. I looked up and down the street. The buildings were all
jammed together like a row of birdhouses In front of each one was a tiny
square of grass, and in front of that was a long, long cement sidewalk
running alongside the cement road.
'Where's the barn?' I asked. 'Where's the river? Where's the swimming
hole?'
'Oh, Sal,' my father said. 'Come along. There's Margaret.' He waved to the
lady at the door.
'We have to go back.' I said 'I forgot something.
The lady with the wild red hair opened the door and came out on the
porch.
'In the back of my closet.' I said, 'under the floorboards. I put something
there, and I've got to have it.
'Don't be a goose,' he said. 'Come and see Margaret.
I did not want to see Margaret. I stood there, looking around, and that's
when I saw the face pressed up against an upstairs window next door. It was
a girl's round face, and it looked afraid. I didn't know it then, but that face
belonged to Phoebe Winterbottom, the girl who had a powerful imagination,
who would become my friend, and who would have all those peculiar things
happen to her.
Not long ago, when I was locked in a car with my grandparents for six
days, I told them the story of Phoebe, and when I finished telling them - or
maybe even as I was telling them - I realized that the story of Phoebe was
like the plaster wall in our old house in Bybanks, Kentucky.
My father started chipping away at a plaster wall in the living room of our
house in Bybanks, shortly after my mother left us one April morning. Our
house was an old farmhouse, which my parents had been restoring, room by
room. Each night, as he waited to hear from my mother, he chipped away at
that wall.
On the night that we got the bad news - that she was not returning - he
pounded and pounded on that wall with a chisel and a hammer. At two
o'clock in the morning, he came up to my room. I was not asleep. He led me
downstairs and showed me what he had found. Hidden behind the wall was a
brick fireplace.
The reason that Phoebe's story reminds me of that plaster wail and the
hidden fireplace is that beneath Phoebe's story was another one. It was about
me and my own mother.