Used to do it as a kid, from about age 9 onwards. At first on the lawn with a meths stove for a breakfast brew, later on, still on the lawn, and then we'd light a fire up on the top terrace of the garden and cook scrambled eggs.
As an adult - in the garden with kids, also completely in the open on the terrace on midsummer day. then started leaving them to camp on their own, with a phone extension in the tent in case of panics. (pre mobile phones)
Good thing, as an adult, about camping in the garden is you can just take your duvet out. For kids, that wouldn't be the done thing at all - you'd have to go the whole hog with proper sleeping bags.
Evening meal is less important, what's important is having breakfast in the tent.
Surprisingly noisy where we are, kids leaving the pub late at night for example. And the garden isn't as teeming with nighttime wildlife as we hoped.But it's still so nice being in the fresh air.