>Can you imagine the sheer struggle it would be for a permaloli to live her daily life?
Yes.
>how would she even navigate it all?
>The bureaucracy wanting constant proof of her age
I imagine the government would have to add some new identifying code on their driver's licenses or IDs that would tell anyone that they're actually permalolis and not someone's daughteru taken for a wild ride. That, and the fact that people at the places she frequent would know her well enough to know her true age, given time.
>the physical limitations
As long as she has a non-manlet husbando to compensate, she should be fine
>the shitshow that’ll inevitably break out if she ever goes out with her husband in public
I think it'd be a lot harder for people to determine who's really a loli and who's a 50,000+ year magical girl when it comes to mamono, but that'd probably be fixed by knowledge of the permaloli herself and of bureaucratic precautions.