So scared

When I first found out I was pregnant I was over the moon excited. I will be 10 weeks Monday and I think it's starting to sink in that I'm going to be a mom. My sister is also pregnant due 6 days after me, this will be her second baby, and my husband gets mad because he says it seems like I'm more excited for her than us. It's just that I know I'm a good aunt I've never been a mom before so I'm just afraid of failing my child or not loving it how I love my niece. Is this normal for first time moms?