I agree with Peter. These people are in call centres and does not know all the details.
Below you can search this for the rules.
Appendix FM Section 1.0b Family Life
Please read page 13-14 and somewhere in page 40. It will show you there that Ella can apply 28 days before her 30th month.
You can also Google this E.LTRP 2.2
Hope that helps