I think that's just fine. I don't think it's indicative of anything other than that my parents gave me my space and didn't helicopter over every little thing. (Additionally, I suppose, my memories of childhood are more of when I was eight or nine, say, than when I was four or five.) My mum was at home, my dad was at work. I played at friends' houses and they played at mine; I played outside on my bike with the other kids on the road, and I read books by myself. Lots and lots of books.
Watching Dash and Mabel going crazy together the other day, a friend commented that they're great friends. Well, yes, they're great friends who beat each other up and push each other's buttons and drive each other nuts on a regular basis. "They're very close," I said, because I think that describes it better. When someone habitually sits on your head or wakes you up by jumping on your belly or thumps you in passing because you told them what two plus two was and you wanted to work it out yourself, they're not so much your best friend as an unavoidable part of your day, every day. And because that person would defend you against bad guys and robbers and bedtime, and holds your hand walking down the street, and is always there to scream beside you as you jump up and down on the sofa, you're okay with that.
I love that. I never had it, and I love that they do. I love that when they think of their childhoods they'll think of each other, not so much of us. The parents should be a constant, that's all. A non-variable presence that provides security and stability and a sense of the where the edges lie - what can be done, what's available, how grown-ups behave in grown-up land. Everything else about childhood, really, is about the children.