Exciting times, Liliana! So sorry about the present home life. That can be really draining.
Once you are 18 you are emancipated and free to go your own way. Your mom can only throw road blocks in the sense of who owns what - smartphone, computer, TV etc. I hope you and the boyfriend have run the numbers on independent living. You probably have enough saved for the first month of rent and security deposit, hooking up gas, electricity and cable, purchase of furniture, electronics, appliances - about $3,000 minimum. How about transportation - does he have wheels? Do you like shopping at Goodwill and the Salvation Army?
Then you have to think of monthly expense - rent, utilities, food, transportation, babysitting, diapers, entertainment. You may be able to tap in to WIC and food stamps, medicaid all depending on his income. Does he have medical insurance for self and spouse at his job? If your joint income will be in the $2,500 per month range you will be at the 125% of poverty level for 2016 family of three.
You will probably have to pass up that college scholarship! Raising a baby the first year is incredibly draining - not enough sleep for a starter.
Your mom will be your biggest resource in these times if you can manage to maintain a decent relationship. She will be more likely to pitch in if you tell her about the pregnancy now rather than at six months. Best of luck!