新概念2.2-breakfast or lunch

Why was the writer's aunt surprised?

It was Sunday. I never get up early on Sundays. I sometimes stay in bed until lunchtime.

Last Sunday I got up very late.

I looked out of the window.It was dard outside.

'What a day!' I thought. 'It's rainning again.'

Just then, the telephone rang. It is my aunt Lucy.

'I‘ve just arrived by train,' she said. 'I'm coming to see you.'

'But I'm still having breakfast,'I said.

'What are you doing?'she asked.

'I'm having breakfast,' I repeated.

'Dear me,' she said.

'Do you always get up so late? It's one o'clock!'