I have to agree that you should not worry about the formal stuff. Having the basic social skills (including practising things like turn taking, sharing, listening in a group, etc as well as dressing, toileting, eating etc) is far more important.
I would say it is better to be curious, interested, excited, enjoy new things, etc than to be 'hot housed' and then 'turned off' to learning.
Schools often have a specific way to teach letters (e.g. letter sounds not names and often more precise letter sounds 'mmmm' not 'meh') and similarly specific letter formation for handwriting especially lower case when appropriate not capital letters through out. If you put a lot of effort / pressure into teaching these things the child can end up at school having to relearn things.
Having a love of books, being read lots of stories to, knowing that where you start to read and how to handle books will all help children learn to read.
Once your child starts school then you can support your child in learning what the school is teaching but don't worry too much. Having a good rest, having fun, having a rich vocabulary of experiences due to lots of fun activities, visits, games, day to day activities is much more important than doing formal activities.
My DS1 is going to school in September as well. He is a July birthday boy and knowing what girls especially Autumn term born girls can do I am quite worried. He also has a speech delay so does not talk that much at pre-school and when he does is very hard to understand. I spoke to the reception class teachers about summer born boys when I visited the schools and most responded with 'we are very used to summer born boys - don't worry!'.
How is the school you want going to settle them in? My preferred school has the youngest in first for mornings only so that they can focus on this very small group for a week to help them learn all the routines and social skills needed. They gradually introduce the older children who then go full time first until the youngest go full time last. I thought this was a lovely way of doing things but not the same in all schools.