Try to be patient with her and forget about her earlier behavior.
What counts is how she acts now and in the future. She probably had her reasons for being remote from you during your pregnancy—concern that her son's career might be ruined by fatherhood, fear that a baby would come between her and her son, etc. Who knows? What is important for both you and your baby—and for your husband—is that she is now trying to heal old wounds and help to create a happier family situation. Babies can be wonderful healers, and the chances are your baby is playing that role. I hope you can let it happen.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.