Well, yes, it’s almost certainly going to be uncomfortable.
You feel the need to set boundaries because you’re tired of how things are after a long time without them, or with poor ones. Which means someone else has been getting something by stepping over where the boundaries would’ve been helpful. So…
They’d rather not see them in place, ‘cos they’ll have to change.
You’ll be uncomfortable putting them in place, ‘cos you’re creating the unwelcome change.
You’ll gain from boundaries though, in the long run. You’ll have more space for what matters. More time. More energy.
In the long run.
Kindly, keep going.