It come natural I believe. I'm not the best with kids either but my son has the biggest spot in my heart more than anyone ever has. You'll do good mama. Don't worry.
Yea it's way different when you have your own. I'm not too big a fan of other peoples children. I used to babysit kids when I was growing up and hated it. You get a different connection with your own.
Its ok some people just aren't baby people but once your baby is born your instincts will kick in plus you can bug the s*** out of your mom and siblings and ask them about things you aren't sure how to do im sure everyone will be helpful :)
You'll be fine, everyone starts to get doubts towards the end. I wasn't terribly fond of kids before having one, but I absolutely adore my son. I've found that while I'm still not a "kid person" in general, it has made it so much easier for me to socialize and play with other peoples' kids.