I really did find, like Snowdrops, that once they had been in secondary school for a while they learned to like sleep more and matured re this issue at least.
When we have girls over for sleepovers now as we do almost fortnightly, I barely know we have them now.
I do remember the first ever sleepover we did, when eldest was 10, that I had to stand in the room until they started to drop off to sleep(after several polite requests to do so).
We didn't do one again for a while.If we had an occasional child who wouldn't settle when they were a couple of years younger, then frankly they were bottom of the list for a revisit.
They really do handle it so much better as they get older and with the far flung distances their friends come from, it is the only way to socialise.
However I suppose it is also dependant on how sensible the group of friends are too.