Mother’s Disapproval

My husband and I have been together for 3 years and married for over a year. We just started ttc but I know my mom is going to disapprove of us having a baby because she wants me to wait until I’m like 35 to have kids but there is no way I am waiting that long. My husband and I are both super excited about the possibility of bringing a little one into our lives but when/if I get pregnant I’m scared how I’m going to tell my mom? She thinks I’m still on BC. Any suggestions?