34 weeks??? Im scared.

I'm at the doctors now waiting this hour because I'm doing my glucose test but a little while ago I asked the doc about when I'm having the c section. Currently 25+4 weeks. I'm high risk for possible pre clampsia again. I thought this whole time it would be about 39 weeks if everything goes smoothly. So she comes in the room with the other doc and they're not speaking to me but I clearly heard something about the c section being 34 weeks or sooner if need be. Is that normal? They already told me my baby was on the smaller side. I think 9th percentile when I had my ultrasound a few weeks ago. My last baby was born at 25 weeks and now I'm kinda freaking out. I Feel like 34 weeks is too soon again.