Why is it important to you (assuming it is) that the Hebrew word almah in Isaiah, Catholic chapter seven, Protestant verse fourteen be not only translated, but believed as virgin instead of young woman ?
Because, unlike the immaculate conception and perpetual virginity, it is clearly and explicitly documented in the Gospels (thanks be to God for giving us His scripture through the Apostles, and for giving the early church fathers the wisdom for recognizing them as such).
Why is it necessary to believe it to be saved ?