(its not it's and fewer nor less by the way - the bits above making me wince)
Xenia - brave of you to correct another poster! may I return the favour?
It's pretty good isn't it? - you should have a comma after 'good'.
It also ensures the individual child is more likely to go to a good university if most of the chidlren in your class are doing so. - it's 'children', not 'chidlren'.
A friend's child at a state school went to an ex poly recently. - ex poly should be hyphenated.
her father is clever. - 'her' requires a capital letter as it is starting a sentence.
He should be able in 2 second internet searching to know given the career she's picked it hugely matters if you're at an ex poly or not but the school and he have either not told her or peer presssure is so high that she wants to follow her friends to the ex poly - where to start with this sentence? It should be 'seconds' rather than 'second' and you require a comma after 'know' and 'picked' since that phrase is parenthetical. And 'pressure' rather than 'presssure'.
I think if you buy a good privaet school place you can ensure the whole cohort is going to decent places given how much peer pressure matters at teenage stage - 'private', of course, not 'privaet'.
I also notice that more people from private schools seem to speak and write better - did you have a private school education yourself, Xenia?