Is it bad if I don't remember what he weighed at 20 weeks? I don't even know if they told me. Every u/s or appointment I was told he was average or just fine.
Ultrasound sizing is notoriously wrong. I was told my baby would be average weight - around 7lbs - and he was 8lb12oz when born. My sister was told her baby would be in the 8lb range, and she came out at around 6lb2oz, a peanut.
I wouldn't worry about it at this stage at all. If your baby starts to develop unnatural or fast growth, the doctors will definitely say something to you.