While there is a cut-off that means she is likely to have to wait, it will depend heavily on where you live. Some areas do a 3 term intake, so while you apply, they may not offer her a place until January, or may offer half days (can you fit this into your schedule?)
Only you can decide if she is ready, but schools do offer a visit day, so perhaps you can judge then.
Only you can decide if she is ready, but schools do offer a visit day, so perhaps you can judge then.
Also, some areas will take a child early if they are very short of pupils - village schools, faith schools, certainly we found this in Wales (and my own year group did this in Scotland back in the dark ages), and schools with a pre-school provision do value judgements on spaces between pre-school and reception. Have you looked at school provided pre-schools? This might be a first step.
My DS went in to reception 3 days after his 3rd birthday, part-time - not academic at all, but very sociable, so we found him helping the older more timid children. You may find though that you have to choose again when she goes to secondary school, and if you move counties at any time, you may find that you have to have a conversation with the new local authority.