Bf complains. Is it possible that I have a short vagina?

Not likely. The vagina undergoes expansion by one third of the back part of the vagina during sexual excitement for females along with lubrication, and elevation of the cervix. It is more likely, that intercourse is occuring before those changes have taken place and you need t communicate to your boyfriend when you are ready, because males are "everready" like the battery.Assist him in helping you to be ready.