Beware of setting a bad precedent
Starting a new job? Have a new manager? Recently promoted?
These are key moments. What you do now will have an outsized influence on how people relate to you.
If you work overtime without being asked to now, if you don't push back on requests that you're unhappy with now, if you respond to emails during nights and weekends now—then that might very well be what people will expect of you in the future.
In this fragile period where you and your coworkers are getting to know each other, it is doubly important to guard your boundaries. Speak up for yourself, even if that's uncomfortable for a few minutes.
You can change people's expectations of you later, but it will be a heck of a lot more work.
Yours,
— Peter