large placenta/maternal lake

I'm about 22wks and this past week I had my 20 week ultrasound. Baby is doing great and likes to do flips..alot..😂😍 but found out my placenta is over my cervix which means placenta previa.. and it also goes all the up the back of my uterus which doesn't really leave room for it to move before time to deliver. I've been put on no intercourse or vaginal exams for the the rest of the pregnancy due to also having Very Large blood vessels around my cervix as well. I also have a Placental maternal Lake that runs the length of my placenta facing baby. you can see the the fluid swirling in the lake on the ultrasound and the specialist said It's the largest one she has ever seen in a patient. has anyone else had one this large before...and if so did it affect the baby? she said depending on how things go i could be admitted anywhere from 32weeks to 36weeks and have a c section come 36th weeks. this is my third baby.