There’s no legal reason you can’t do whatever you want.
There’s also no legal reason for your mom and sister to let you keep living there.
The worst-case scenario is that your mother kicks you out of the house. Which, in my opinion, wouldn’t be a bad thing for you if they do this because they’re upset you went on a date.
You only live once
The US has double taxation treaties with over 60 countries. When you pay taxes somewhere else, you deduct all of that tax from your US taxes above the $125k.
Though I definitely agree the IRS shouldn’t need these treaties, because if you’re not living there, why should you even need to file?