Pregnancy pumping and breastfeeding

I know it’s safe to breastfeed and pump while pregnant if you were already doing it. I’m currently breastfeeding my 16 month old but not pumping.

Do you think it would be okay to add in one or two pump sessions a day?

My 16 month old was a preemie and it was hard to keep up pumping after he was born and tube fed (had to use donor milk once)

I was thinking if I started pumping now, and put it in the freezer, I’d have backup milk for this baby should it also come early.

I can’t ask my doctor as they basically said to wait and ask questions at my 8 week appt and haven’t answered anything else I’ve asked 🙄 my midwife from my last pregnancy is out on medical leave so I can’t ask her either 😫