Having a baby should be the sole decision of the parents and most importantly the mother.
During pregnancy, a lady goes through so many changes. Not only does her body change but also her mental state also changes. A lady should be mentally and physically suitable and stable to give birth to a baby. A lady should have the only right to decide the right time to conceive.
In many cases, it has been seen that a mother goes into depression after giving birth unwillingly. And some ladies, who don’t want a baby but get pregnant go into “Denial Pregnancy“.
Pregnancy denial is a term that refers to the condition in which a woman denies that she is pregnant. At 20 weeks of pregnancy, it is found in 1 of 475 women, but the incidence declines to 1 in 2500 at delivery. Pregnancy denial may occur in both psychotic and non-psychotic forms.

Your mother must be impatient to meet her grandson/granddaughter but she should understand that it should be your and your wife’s decision when to have a baby and she should respect your decision.