I imagine that DD will be academically motivated - DH and I were and she is similar to us at the same age. She was an early talker and the subjects that interest her are not the most conventional.
I know she is a bright child, whether she is a very bright child, whether she is motivated, whether she has any SEN and whether she would be suited to a high pressured academic school is still to find out.
At the moment she is at a CofE primary's nursery class. Next year she will be going to the local state primary. In the meantime I am sussing out the options should the state primary not be able to meet her needs (whatever they may be). I will be taking a keen interest in what she is doing - but not to the extent of marching in every 5 minutes. I am told that this particular primary is good with the very able students so I will be interested to see how it works in practice.
If she is academic then we would like to sit her for some of the super-selectives at either 7+ or 11+. This will mean tutoring so that the exam syllabus is covered - it isn't until well after the exams in most state primaries. So we will need to have a fair idea if it's worth pursuing earlier than would be ideal in order to fix that up.
I would consider all your options, familiarise yourself with the different hoops to be jumped through for each and then support where you can and have plans in place to help should your DC have problems along the way or if you are not happy with something.
If you are trying to suss out primary schools to apply to, then my methods have been to read the Ofsted, look at the Value Added, and more importantly look at the %age of children getting Level 2 at KS1 and Level 5 at KS2. I would prefer a Good school that gets 70% Level 5 at KS2 than an Outstanding school that gets 20%. Interrogate every parent on buses, in Tescos, on the swings, doctors surgery etc about the school their DC is at and what they think.
Not sure if that helps at all...