To be so worried about school readiness that I’m struggling to enjoy the last months before school

And this is why teachers have to waste time dealing with the personal hygiene of children who should be learning to write instead. It actually does matter now because it results in lost learning time for all the other children. The idea of sending a 4 year old to school in a nappy, assuming no SEN, is absolutely insane. How about the OP actually parents her child?

You’re overthinking babe
He’s starting school whether he’s “ready”
or not. End of. So don’t worry. You are an engaged and interested and proactive mum so severe SEN aside he will be absolutely fine. That’s absolutely all they need, a parent that gives a small shit and then they’re fine.
Neither of mine have ever pooed at school, at risk of invoking the poo troll I have never pooed anywhere except my own home or a holiday home/place I am staying overnight. Put a nappy on him when he gets in if needed.
Getting dressed? They are all fucking awful at that but slowly as their mates are doing it he’ll catch on.
Fast forward a bit. He’s 18, he’s off to Uni. You’re dropping him off at his halls and saying goodbye. Everyone’s crying.
Are you having to pop a nappy on before you head home so he can have a poo? Do you need to get his joggers off and his jeans and shirt on so he can go clubbing?
No and no. Literally don’t even worry about this again. If it will sort itself out.
If it won’t matter in ten years then it doesn’t matter now.

He’ll be ready in his own time. I really wouldn’t worry. There really is still so much time.
My son still had a night time nappy in the first year of reception. He barely used it but it gave him reassurance.
He is 10 now and still prefers I read to him until he drops off. It’s one of my favourite parts of the day. We natter about school and then read novels together 😊 I know these days are numbered.

Just try to enjoy these last few months. His confidence will grow and grow. Try and encourage him without getting too anxious.

Maybe you do need to force the pace here? He can't start school unable to use the toilet and it's not going to happen by magic.

That's what I was going to say. What's the rush? He's so little and on his own timeline. Such a shame to spend his last few free months like this.

Agree that it's a long way til September, they are still changing and learning so fast at his age.

I would really try to take a focus off school as some kind of hard-line point by which he must have ticked all these boxes, and just think of things in their own terms (sorry I can't quite express it right!) so with the toilet stuff I would say that's something to address in itself as obviously it will be better for him when he's comfortable doing a poo out of a nappy. If he kept doing that for a long time it would be a sign of concern in itself.

But the dressing and the sleeping - totally normal for his age and it really doesn't matter that much in the scheme of things. Yes they want kids to be able to dress themselves ideally but it's things like shoes and coats more than socks and it's not a sign of concern in itself if a 3 or 4yo struggles with dressing.

Try not to compare him with others (including yourself!) but if it does help ease your sense of impending failure, my summer born 4yo is at school and....
...is tiny and looks like the younger sibling of some of his new friends 😂
...can't put on his socks, just about does his velcro shoes but always on the wrong foot
...shows no interest in picking his own clothes and doesn't dress himself cos we never have time for it. Can just about undress in eve.
...hated nursery drop offs, cried intermittently for years (happy in the days) but absolutely loved going to school. Hesitant on the first day or two ran in pretty much from then on, and has only had one day of tears when it turned out he was coming down with a bug
.... Wasn't especially interested in writing or sounding out letters before he started - except to recognise initials of his own name- but now can read at the level expected of him and form letters the same
...still has a parent with him every night going to sleep, I usually cuddle him in the bed. My 10yo also still likes a parent to sit with him and 12yo too on occasion when he's upset or whatever
....still wakes up and comes to our bed every night

If he only feels comfortable to poo at home, that’s not a big problem. Plenty of children can be later with that aspect of toilet training. My own child was. As far as getting dressed, at our school they come dressed for pe already on pe days (I think this is quite common post covid) and plenty of reception age children still ask for assistance with coats, gloves etc, which is given. Independence is encouraged of course, but help will always be given with toileting and dressing where needed. Try not to let it worry you too much. He will get there in his own time.

My dd was a summer born and I wish I had held her back a year. I would really consider it OP. Hopefully he will get there though we were lucky that chocolate always bribed ours to sit in the potty. Is he a bit constipated? Might it hurt when he goes?

@JagerPlease you must be exhausted after 8 years + of night wakings! 😩

So he'll have just turned 4 when he starts? I would wait until next September if you don't think he's ready

If it helps, my 8 year old (in y4, august born) would also do anything to avoid getting himself dressed, and still doesn't sleep through the night. He's never had an issue getting changed at school, and is flourishing on all counts.

Your son sounds like he will be more than ready for school in so many other ways, the toileting and getting dressed will come. And you may find it comes naturally once he starts school and wants to fit in with his peers

He's simply too young to go to school. You send them far too early in the UK, just wait a year.

I wouldn’t worry too much. They all develop at different stages. You still have ages before school and a lot can change in that time.
Worst case scenario he holds poos during the day and does them in a nappy at night. Well that is ok.
He doesn’t dress himself well for going outside and needs help from the teacher. Ok, they are used to that (and a bit of pressure that everyone else does it themselves and ends up outside sooner will motivate him).
None of what you are saying is awful. Breathe, keep reading to him and stimulating him, keep chipping away at other skills. He will be fine.

Why start him in September 2025? He can start in September 2026 and enjoy play based learning for an extra year and start school when he is emotionally and physically more ready.

Six months is a long time at his age, or rather seven until September.

Keep trying, review again in May. What I found with mine was they did whatever it was very shortly after the point I started to panic!

Keep a journal of progress to help you see it.