Hey mama, first thing, please keep close contact with your OB and follow their monitoring plan, since this really needs proper medical tracking given your history with placenta previa.
I get it, the worry is real, especially knowing blood bank prep is in place, that shows your doctor is being cautious which is actually good. From what I've heard from other moms, the waiting-and-seeing approach your OB mentioned does happen often at 25 weeks because things can shift as pregnancy progresses, so there's hope there. Honestly, beyond what your doctor says (rest, avoiding heavy lifting, watching for warning signs), there's not much we can "do" to change placental position ourselves, it's one of those things we have to let our bodies do. Pero stay calm as much as you can, attend all your scans, and don't hesitate to message or visit your OB if anything feels off. You're doing everything right by being aware and prepared.