What is the average lbs for twins ?

Hey guys ,
Just  found out we are having twins , and I'm so scared.  My husband is a big guys 6ft and wide build . His son from first marriage was born 10lbs. I'm only 5'4  so my so scared I won't be able to hold the twins full term. I also have scoliosis and take muscle relaxers for spasms daily.  Pls tell me I won't be having 10lbe babies