Low placenta at 19 weeks + flu shot during pregnancy

So on Thursday my doctor had me come in due to me experiencing sharp pain in my abdomen and I noticed tiny specks of spotting when wiping. They did a vaginal ultrasound. Baby was fine he was trampling my cervix lol which explains the pain. My cervix looked great according to the doctor but she said my placenta was a bit low ? They like it to be 3 cm or something away from the cervix ,,?? I forgot 😫 but mine was like 2 point Something and she said that could later result in me getting a c section done. I was 18 weeks and 6 days that day. I am 19+2 now. She said chances are it might move up by 24 weeks. Did anybody else have this issue? What was the outcome ?? She told me I didn’t need to worry about doing pelvic rest at the moment. And they’ll keep an eye on it through ultrasounds. I really don’t want a c-section not that there’s anything wrong with it but I want to try having a vaginal delivery unless there is risks to that for me.

Also she mentioned a flu shot will be recommended to me at my next visit. Did you ladies get a flu shot?? I tend to get sick towards the end of the year when it’s colder and I’ve never gotten a flu shot before. I don’t know what to do about that.