Your only 17 years old and you have a lot of time to have a baby. Wait until you two have your own place and a stable income and dont have to worry about or relay on his mom. What is so bad with waiting to be married? Dont you want this child to have the best life possible and the biggest oppurtunity to suceed in life. Trust me I know how bad you want a baby but wait until the time is right and you dont have to worry about problems like these. Think of how much better it would be to have your pregnancy be exciting and everyone to approve. Now I know this doesnt happen all the time but if you two are already planning on getting married then wait, be married awhile then ttc. His mom wont have anything to say about it then. Trust me the first year of marriage is tough enough without a baby. Give you and your boyfriend time to just be with each other and enjoy being married and spend all of your time in bed together and enjoying each others company. You can still be a young mom at 20,21,22,23 and so on. If he is having doubts about it then it is probably not the right time. Wait and let it be a happy experiance for all involved. Wouldnt you rather tell your son or daughter about how happy you were when you were pregnant, not that grandma kicked out your dad and wouldnt talk to us for months?

Ultimatley it is your decision, good luck.