I wish I had known how much being a parent would change me. I was young when I had ds (24) and now I'm 26 (he's not quite 2), and I've grown up more in the last 2 years than I ever could have imagined. What was important to me, is now just kind of a bonus - ds is SO much more important to me than ANYTHING else ever could be. Before he was born, it was just so abstract, I really had no idea.
Theres no way to know this in a concrete way until you are a parent, but I've never loved anyone as much or as deeply as I love my baby. It's an incredible bond, and he is the most amazing person I know (seriously, he was INSIDE MY BODY?!?!?!?) It's so surreal almost to think that I was pregnant with him - he came from ME?? How did that happen? As much as I read and learned about pregnancy, its just so surreal and abstract still. I had no idea how amazing being a mother is, or how hard it is! It's by far the hardest thing I've done, and labor and birth are only the start - everything that comes after is so much harder, and so rewarding (although labor/birth is the most rewarding b/c thats when you meet them the first time! Evolution really knew what it was doing!) Seeing ds grow up is so amazing, getting to know his personality, watching him learn new things, its incredible, absolutely incredible. I had NO idea!
All that said, even though I love motherhood more than anything, I'm not cut out to be a SAHM, and thats ok. Some people are, and I admire them. I need my space to be me, and to do things for me and my ds in ways that being a SAHM wouldn't work for me. It's great to want that, or to not want that, just be aware that parenting changes us in so many ways - be open minded about what you will want/need after the baby comes, and realize that those things may change as your baby grow. Thats ok. It's normal. It doesn't make you a bad mom! Motherhood is such a guilt-trip to begin with, putting pressure on yourself, or allowing others to make you feel guilty about working/not working/WAH/SAH/working part-time/whatever, is not a good idea! Be secure in who you are, enough that if you change (b/c you will), you're ok with it. It is ok, everyone, and every mom is different.