Yea my fundal height is measuring big but at my 19 week u/s the baby was already measuring 2 weeks bigger than he should have been. Everybody has been asking me if I'm due any day or if its twins cuz I'm so big. Although I was big like this with all of my kids, I'm bigger now than when I was when I delivered my youngest. I'm pretty sure he is gonna be big, I just don't know how big. My doctor said that he hopes that he isn't real big because he would rather me have him vaginally than having to have a c-section.
I assume you're measuring big because of your fundal height? That can be off for many reasons, increase in amniotic fluid, position of baby, fluid intake, etc. So it doesn't necessarily mean your baby is going to be big. If your baby IS measuring big, it depends, your other kids are actually pretty average so I don't think you'll have a problem having another baby around that size. I have a friend that is 5' and had a 9lb 10oz baby naturally. I, however, had 2 kids via c-section because I'm 4'11, and my first baby was 8lbs 9.5ozs, my second was 8lbs 12ozs, and they just wouldn't fit. Since you've had 3 previous vaginal births I doubt you'll need a c-section. If you do end up having a c-section it's really not bad, I loved my c-section experience, it's such a cool/amazing feeling, and I'm terrified of surgeries, recovery is really not bad either. Good luck!!