School year confusion, maths help please!

[ShinyWorthKeeping]

I'd like to preface this by saying I'm completely dyscalculate, so please explain this kindly but slowly

I was born September 1990, my sister was born March 1992. 18 months between us and she was in the school year directly below me.

DD2 was born july 2024 so due to start school 2028. I am expecting DC3 in September 2025 so 14 months between them, with a school year in between them, (DC3 starts school in 2030).

How is this possible?? How can there be 14 months but a school year in between when there was 4 more months between me and my sister and she was in the year directly below me?

There couldn't be children in lower years older than a child in the year above them so what am I missing?

I'm going to go draw a diagram it may or may not include those horses I'll report back...

And remember your fact is true, so hold on to that:
There couldn't be children in lower years older than a child in the year above them

What about summer borns who are deferred? They could be older than children in the year above. (But I know this isn't what the op is confused about.)

Let's leave aside deferrals for now.

Done one for you OP. This should help. I’ve shown the birth year and the year starting school, and highlighted you and your sisters dates, and your children’s dates.

Posted before I saw this...

Yes.

But that's not what your examples are showing because you're not comparing fixed points.

'In your example you have a child (A) in Year 2 born in September who is 18 months older than a child in Year 1.

And then you have a completely different child (B) in Year 2 born in July who is 14 months older than a child in Reception.

You are comparing two different children.

From the perspective of child A - they are 18 months older than the child in Year 1, and 24 months older than the child in Reception.

From the perspective of child B - they are 8 months older than the child in Year 1 and 14 months older than the child in Reception.

No contradictions.

Edit: Never mind, the diagram above explains it better.

@JimHalpertsWife omg I get it! Your timeline has been very helpful! Thank you!
@Talipesmum I don't understand your graph but I'm grateful anyway.

Thank you everyone who helped
if I think about it too hard without looking at the timeline I get confused again

It's because of the way round the differences are in terms of the school year.

You are 14 months older than your DSis but you were born right at the beginning of the school year and your DSis was born mid year. In your case there could be up to 23 months between you and your DSis and you'd have still been only one school year apart.

Your DD was born right at the end of a school year, so the maximum age gap between her and your DC3 to separate them by one year is only 13 months.

I've put it on a spreadsheet, using the school year as the top line, to show when you and your sister were born versus when your DD and DC3 is due.

Hopefully this will help visualise it for you.

If DC3 comes early in August, they will only be one year apart (and DC3 would be one of the youngest in the year, rather than the eldest if they were born a month later).

Great minds think alike! 😂

Try pretending that the school year starts on 1 January instead of 1 September, that you go to school in a year if you were 4 years old on 31 December of the year before, and everyone was born 4 months later than they were. That changes nothing about the relative ages and might make it easier to see how it works because there is no confusion possible with the different types of years. So your original post would become (my additions in italics):

I was born September 1990 January 1991, my sister was born JulyMarch 1992. 18 months between us and she was born in the school calendar year directly below me.
DD2 was born july November 2024 so will be 4 in November 2028 and therefore due to start school 2028 January 2029. I am expecting DC3 in September 2025 January 2026 so 14 months between them, with a school year in between them, (DC3 starts school in 2030 January 2031, because they will only be 3 years and 11 months on 31 December 2030).

I don’t really understand your thinking?

My children are 3 years apart almost but only 2 school years as 1 is September and the other is August

Also should have said a special thanks to @Comff for believing in me and cheering me on even though I bet I was extremely frustrating!

If DC3 is due on 1 Sept and born on their due date or later they will be 2 school years below DC2.

But if DC3 is born a day early on 31 Aug there will be almost exactly the same age gap but they would then be in the school year below DC2.