General achey body - parenting 2 children

I have a 6 month old and a 4 year old and feel like I’m constantly on my feet (naturally sorting housework, getting them things etc).

I feel so achey all the time! Just little aches eg knees, back. I’m only 35…

Is this just age? Natural consequence of 2 small children?

And will anything help eg yoga, Pilates?