I'm really having a hard time seeing myself as a soon to be mom... like I look in the mirror and I…

I'm really having a hard time seeing myself as a soon to be mom... like I look in the mirror and I don't see mother material, I see a young girl who has no idea what's she's doing with life or what she's getting into. It's so hard for me to see myself as being a wife as well... I've been married since August but every time I look in the mirror I think I look way too young for any of this. I wasn't freaking out so much before but now that I'm only a couple weeks away from having a son, I'm a nervous wreck. I don't know what to do, what to think, or what to expect. I'm so afraid of not being a good mom, I'm barely a good wife...