How long will it take for my milk to come in?

Kaitlyn
I had a cesarean yesterday morning. My nurses just keep telling me to let baby feed on the collostrum (not sure if I spelled that correctly) until my milk comes in. They say it should come within a few days but I'm worried that just collostrum won't be enough for her until then.. She feeds every hour and a half to two hours. 
I feel so dumb because I have no idea what I'm doing. I'd originally planned to formula feed but I changed my mind last minute so we didn't have time to take breastfeeding classes. Ugh sorry guys I just need help. I wish I knew what to do. I feel like such a fool. 😔