Okay mama, good news, mid-lying placenta isn't something to worry about kasi hindi siya previa (which would block the cervix), at kung cephalic na ang baby mo, that's the position you want para sa normal delivery. Grade 2-3 maturity at 37 weeks is normal din, it just means the placenta is aging as it should, kaya you're good there. I'd still run this by your OB just to confirm lahat okay lang based sa full picture ng ultrasound, pero honestly marami akong kakilala na had mid-lying placenta and normal delivery sila, walang drama, you're likely fine!