Which Date is correct?

[Phoenix]

I'm just saying that the Registrar's maths may have been a trifle faulty

[Kit]

Maybe he just turned a blind eye??

My 2g grandmother was baptised 2 days before she was born and the birth was registered within 6 weeks of either date.

Everything datewise seems reasonably consistent until we get to the 1939 register. The DOB she declares there is 3.5 years earlier than her birthday.

So now I don't know what is correct. She never appears on a census with her mother. She is baptised twice, in 2 different names. I am only assuming her father is the man whose surname she used. Mum only married him when she got pregnant with child number 5.