Please don't worry and definitely don't hothouse her!!!
Her reception teacher will be quite happy if she can take herself to the loo, get dressed/undressed for PE, sit quietly on the carpet for a few minutes, that sort of thing. As hester says, if she knows her letters, count to 10, recognise her name etc, then marvellous. I really wouldn't worry about anything else.
FWIW, out of the 60 children who started school with DS1 a few years ago, very few of them were reading. Several of them could write their name - but the reception teachers cheerfully informed us at the curriculum evening that not one of them could write the letters in their name properly, so those children had to relearn letter formation anyway.
DS went into reception unable to read or write and was certainly not able to do things like subtract 4 from 10, but (now end of Y2) is above average for both literacy and numeracy.
Don't panic. And ignore the boasting brigade. Half of them are probably lying, and the other half are most likely exaggerating
Just enjoy the summer with your DD - you will never get those preschool years back again.