I can't say about the law as this is mainly a UK site but I hope that everything works out OK for you.
How are you at saving? Can you try and put as much money by as possible so you have a safety net as well as some money to start you off.
Can you sit down with your boyfriend's mom and see if she can help you go through a budget with you (it's hard to know what you will and won't need til you're out there in the real world) so you have an idea about how much money you can allow for what.
Always have a back up plan, as you're so young, if there someone you could go to should things not work out with your boyfriend's family?
Keep in mind whether you could afford to live if you had to support yourself, accomodation etc... especially if you want to carry on your education.
Could you try things out on a temporary basis, stay with your boyfriend's family for a while while you try and work things through with your mom and see if you can make the relationship better?
It sounds like you do talk but that you just end up arguing and saying hurtful things. Could you both agree to try not to get into an argument and maybe walk away and calm down then come back and talk about things?