That's 'half way through the bloody day' is what my Dad would have said, I can hear him now 🤣
My Mum would think it, but not say it, but then blather on about what she's done while said person was still in bed.
I've always been a morning person, but I'm also a night owl & don't sleep well in between. I'd sell my soul for a decent nights sleep.
I love the early hours of the day, but if you're happy as you are then just ignore her. DH is up with the youngest - it's not like she's roaming the house on her own playing with knives!
Have you found another house yet? I'd be onto every agent as they sometimes don't even get as far as advertising a house and I'd be on Rightmove with my morning coffee!
Although it's nothing to do with your Mum, it kind of is while you're living there. I find it a little bit annoying tip toeing around the house if someone is staying & sleeping in, but I accept not everyone is up at 5/6
Depending on how old your Mum is (how her life has been) she might genuinely feel you're putting your marriage at risk expecting/allowing your DH to get up and look after your DD.
Maybe your night owling is disturbing her sleep? I struggle to sleep if others are still up.
Next time she goes on about it, ask why she thinks that.
Good luck house hunting!