So dyt I should do 10pm BT
I can only tell what I'd do - and yes I would. I'd do 10pm and make sure he has no chance of falling to sleep before hand.
I'm actually bracing myself for when DS gets to this age/stage, I've seen a few threads on sleep needs dropping at around this age and have been thinking how I will prepare for it and deal with it. In our case I do feel lucky that I can count on reading time in the morning and (FX) when he is older he will understand he can turn on a lamp and read but must stay quiet, but even so I still wouldn't want him to be waking too early.
Whilst I don't think 10pm will be your fixed BT, it's just the time you go to now to shift his body clock, I would probably prepare yourself for his sleep need being lower than it has been to this point. You may need to think about the evening routine and how he will entertain himself or spend time with you in the evenings too.