AITA for not getting up at the same time as my 8 year old?

I live with my partner and our son. At weekends my 8 year old son likes to get up at about 7:30 to watch cartoons downstairs. My partner will always make sure she follows him downstairs and criticises me if I don’t get up at the same time as I’m missing out on time with him. I get up at about 8:45 normally.

To me, I enjoyed getting up before my mum when I was a kid and it was nice to have some alone time doing what I wanted. My son has been happy to play by himself when my partner is away until I get up about an hour after him but my partner thinks I should be up every moment that our son is and tries to guilt trip me saying she has been up early dealing with him when I’ve lazed around in bed. So it’s actually twofold, I should be up to be with him and also to relieve her of her “duties”.

To me, none of this is necessary. It’s not like I’m getting up at midday.

AITA?