Back to work interview?

Hello,

I'm wondering if anyone can help me or has had the same. I have been sent a letter telling me I have a back to work interview next week.

However my partner claims income support for the pair of us, he is a full time carer, and I am a stay at home mummy, I have two young children, one aged 1 (soon to be 2), and another almost 4.

As far as I was aware I am allowed to be a stay at home mum until they both reach school age? Not that I want that long, but I'm not ready to leave my 1 year old in child care.

Is there anyone that can clarify?

Thank you