Think I already read somewere here that most mothers don't beleve a woman good enough for their son even exist :)) So don't take it personal, dear, we all are facing this attitude in one way or another. Just make sure to become a fairy mother-in-law for your future daughter-in-law, not a witch as the one you are facing now :))
Try not to be too direct with your mother in law about this as it can be a delicate subject for her. Instead, observe for a while if she is truly acting in a way that shows she is unhappy with you. Concrete evidence would be a much better approach than using speculation alone. In the meanwhile, be courteous to your mother-in-law, but also make sure not to let her bully you. Speak to your husband about this issue if it goes out of hand, and perhaps he can help mediate things between your his mum and yourself.
Usually mothers-in-law are doing what they feel are best for their sons, and sometimes may be a sense of loss especially their son who was so dependent on them before the marriage are now not so quick to come to them with any problems they may have. She can thus feel threatened, which can also make you feel the same. It is important to tread carefully in this case, and do not put your husband in between yourself and his mum as it might cause family strains.
In-laws are often difficult to please, but that doesn’t need to threaten your relationship. Your spouse’s parents are very interested in seeing their child happy in marriage, and for one reason or another, your in-laws have their doubts. You shouldn’t worry too much about their thoughts on your marriage, though. As long as your spouse isn’t listening to their advice, you can be very happy in love despite their feelings right now. If they are good parents, then seeing their child in a fulfilling marriage will be all that’s necessary to win them over in the long run.