There are no assessment criteria to join/rejoin school. Your daughter would go into the school year which matches her age, even if that is ill-suited to her individual needs. Rarely, a school may put a child into a different year group if there are strong reasons for it.
She will definitely be entitled to a school place whenever you want one. However, if the school you want is full, then you'd either have to send her to a different one which does have a vacancy, or continue home educating while waiting in hopes a place will come up at your preferred school.
I've home educated two kids. The eldest has no special needs and we home educated just because we preferred it. That child tried school aged nine and found it very easy to fit in, despite having done no formal education at home. The younger one never went to school because I was so sure it wouldn't meet her needs.
My view is this. If the child is suited to school, there's no disadvantage to waiting, and may be some advantages. For example, when my kid trotted off to school at nine there were no issues with toilet accidents, fear of a new environment, losing clothing, not speaking up when they had a question, or feeling overwhelmed. Nine year olds are more mature and independent than four year olds. What is daunting to a little kid is no big deal to a big kid.
For a child like my younger one, school was never going to be a good fit. I was sure that keeping her out for at least a couple of years was the right thing to do. Even if I had later decided to send her, having started off at home would have given her a good start to her education. Her social and emotional needs were easier to meet, and she had one-to-one attention for her education. So I figured she would have entered school with greater confidence and better education at (say) six than if she had gone in at four to flounder.
Also, by six her needs would have been clearer and I wouldn't have been fobbed off with the idea that she might just be a late bloomer. I could perhaps have got an EHCP in place for extra help BEFORE she started, so her early experiences of school would be positive. The special needs system is predicated on the idea of putting kids into a mainstream setting and making them try and fail to fit in before any accommodations are offered. That may be economically efficient, but I think it is cruel. Many of the schoolchildren I know who have SEN have low self-esteem because of this. My daughter doesn't. She's never been given the message that she "should" be able to read by a certain age, or do arithmetic of a certain standard, or sit still when she needs to move around, or have friends of her own age. She is where she is, and she's following her own path.