The DCSF definition for SEN is (children who have) "learning difficulties or disabilities which make it harder for them to learn or access education than most other children of the same age"
Your DD does not seem to qualify.
It's fine if the school is using the SENCO to help support your DD but you'll need to be cautious about this too. Your DD will almost certainly not get a statement and not get any funding.
If she's far ahead of her peers, I'd also ask to see the school policy on able and exceptionally able children. Ask them how much and what they do under the (mandatory) G&T program, speak to the G&T coordinator at the school and/or the Leading Teacher (who may work across the whole cluster of schools) and read up on the G&T. If you request your local authority they'll send you a copy of their own G&T policy and what they expect of schools in their area. There's a lot more information on the National Strategies site and elsewhere.
If DD qualifies, you can challenge the school as to why she's not already on the register and write to the Head about it. Being on the register is not itself any guarantee of anything but it will arm you for future "meetings" with the school and allow you to take the case further. More details later if you need them.
You say in your other thread "her reception teacher ... didnt want her to be pushed at a young age"
It's not in her interest to be pushed but it's certainly in her interest to progress at her own speed even if that speed is faster than what's convenient for the school.
As others have advised you, it's best to keep relations with the school cordial at all times and to come across as someone who wants to help them and work with them to achieve an outcome that all of you identify is desirable.