My ds is newly 12. His 'bedtime' is to be upstairs by 8.00, into bed by 8.30 for reading and lights out by 9. In reality I don't go and insist the lights go out unless it's coming on for 10. HIs alarm goes off at 7.15.
He needs his sleep and is miserable and grumpy if he doesn't get enough. I have let him stay up later on a school night, he simply can't get up when he needs too.
He protested his bed time in Yr 6 as all the dc in his class stayed up much later. During SATS tests we had a letter from his teacher suggesting all dc went to bed early for a week before and during the week of the SATS.
I asked his teacher about this as I felt his bed time was fine and couldn't believe that children were going to bed as late as 10 or 11pm at that age. She confirmed that most did and it was clear to her which they were as they were tired and didn't cope so well in class as a result.
He was doing scouts which finished at 9pm. It was a struggle for him but he refused to leave early 9didn't want to loose face). However since starting secondary he simply can't handle the lateness of it as he's getting up more than an hour earlier now so has chosen to drop it.
Given the chance he would be on his laptop all night long. Many a time I have insisted he heads upstairs while he tells me he's not tired. When I pop upstairs to check something not 10 mins later he complains he's too tired to talk and please let him sleep...
So OP I think you as a parent need to look at your situation, what you and your child need and not worry about what anyone else is doing.
I also believe that 'grownup' time for me downstairs is important. We have a small house and there is only 1 space downstairs which we share. The tv, computer, phone, music, homework etc is all in this space. I work and pick ds up from school so am with him from 3.30 pm till he goes upstairs in the evening.
While I am on my computer (like now) I am also having to endure the tv, him chatting away, the radio is on (for me). His choice of tv is also largely cbbc which bores me to tears frankly.
I don't think it's too much to ask for an hour's peace to myself simply to relax. It is the only me time I get and quite often I need the space and peace to get on with chores like the ironing.
So while we have plenty of time together I also need time to chill out myself, otherwise I'm a horrible grump too.
I see nothing wrong with insisting I get some space to get on with the things I need too of an evening.