Red pen uncapped: spelling, “in to” could be into, “there” in first line should be their, the next line could read “The family comprised of a mother, father and their 8 year OLD (you left that out) son named Demetri.” Try to take out ‘was’. And the next sentence also used ‘was’ way too much. "A strange thing happened when I passed Demetri’ would suffice and save you characters. Family cat or pet cat, but family pet cat is overkill, and again, you want to save characters. you could cut out ‘but the fact remained’ if you want, or leave it and put in a comma. Then you have a long run-on sentence. I’d break it up before the ‘and’, into two sentences. “that would give me time to gather engergy…”
And that’s my red pen.
I like the short introduction to the family, so you leave room to build suspense, but then you tell us how bored Millie is and that takes away from the build up. She should be plotting how to save energy and how to appear. just my opinion.

Thank you ElshaHawk for highlighting those errors and unnecessary wording. I fixed it now as you advised and I do think it now reads a lot better. I’ll fix up the other chapters as soon as I have some more spare time.