We know that Catherine is a tomboy, judging from the following passage:

" she was moreover noisy
and wild, hated confinement and cleanliness, and loved nothing so
well in the world as rolling down the green slope at the back of
the house..."

And the lines right before the ones quoted above show us that Catherine is a good sister, for with all these symptoms of profligacy at ten
years old, she had neither a bad heart nor a bad temper, was seldom
stubborn, scarcely ever quarrelsome, and very kind to the little
ones, with few interruptions of tyranny..."