Is it normal for me to have resentment toward my pregnant girlfriend?

Yes I guess it's normal because you don't want the child. But she does. It's her body and what she's says goes at the end of the day. It's all fine her saying she'd get rid of it before but she probably felt the "connection" to the baby once she actually found out she was pregnant. Just don't be a dick about it and support your gf and baby.