Technically, "normal" does not mean "right", it means "as of the norm, the average or standard". I suspect if she said "average size", it would not have bothered you as much. As Calypso mentioned, single-digit sizes are not the "norm" when you look at the total population.
It's unfortunate that today's emphasis on physical beauty as the most important attribute of personal value has resulted in women turning on each other. The OP may find "real women have curves" to be hurtful, but so is, "If you're not thin, no man will love you."