Well...there are lots of issues here (believe it or not). First of all: the Hebrew word in question is the same in the Hebrew Dead Sea Scrolls as it is in the Hebrew Masoretic Text. Now, this is important: ***the most specific English translation that is accepted by practically all experts is "young woman".*** If you get more specific than that (for example: "young woman never-married"), then you have entered the area of scholarly dispute. Scholars are divided - not SOLELY on religious grounds, as you suggest, but often on religious grounds. Please be aware that the PRECISE meanings of the word ARE NOT CERTAIN, are not KNOWN by even the experts. One scholar makes an EXCELLENT case (based on the uses of that same word in same-period texts, most especially other Bible documents) for concluding that word is (almost?) always used with the meaning "young, marriageable woman" or - in more CONCISE English (which is GREATLY PREFERRED in Bible translation) "maiden". Indeed: (in my INEXPERT opinion) "maiden" is an EXCELLENT English translation as it has merely THE CONNOTATION "virgin" without demanding such a meaning. *** But the fact of the matter is that language scholars remain divided on the more precise meaning of the word, and can only agree that "young woman" is accurate. That is: they CANNOT agree if a more precise definition (such as "virgin" or my preferred "maiden") is or is not accurate. *** In support of the translation "virgin" is the fact that the authors of the Septuagint were Jewish scholars of the early centuries B.C.E. That is: they were likely MUCH more expert in the Hebrew of the period than are modern Hebrew scholars...and they chose to translate the word as "virgin" (well...in Greek, not in English, but the point is that they could have used the Greek word meaning "young woman" and instead they used the Greek word meaning "virgin" - note: to translate that Hebrew word in this particular passage, NOT to translate that Hebrew word in all Bible passages, which goes to show that the word DOES have multiple meanings, and extremely likely "virgin" is ONE accurate translation depending on the context). {{ http://www.bible-reviews.com/oldstuff/topics_accuracy_words_almah.html }}

A young girl giving birth is not much of a sign, but a virgin giving birth--now there is a sign. It is confirmation of Genesis 3:15 "The seed of the woman" and also the way God chose to get around the blood curse placed on Jeconiah. https://www.khouse.org/articles/1998/73/

The Dead Sea scrolls do not say any thing about it.

The Hebrew word in Isaiah 7:14 is “almah,” and its inherent meaning is “young woman.” “Almah” can mean “virgin,” as young unmarried women in ancient Hebrew culture were assumed to be virgins. Again, though, the word does not necessarily imply virginity. “Almah” occurs seven times in the Hebrew Scriptures (Genesis 24:43; Exodus 2:8; Psalm 68:25; Proverbs 30:19; Song of Solomon 1:3; 6:8; Isaiah 7:14). None of these instances demands the meaning “virgin,” but neither do they deny the possible meaning of “virgin.” There is no conclusive argument for “almah” in Isaiah 7:14 being either “young woman” or “virgin.” However, it is interesting to note, that in the 3rd century B.C., when a panel of Hebrew scholars and Jewish rabbis began the process of translating the Hebrew Scriptures into Greek, they used the specific Greek word for virgin, “parthenos,” not the more generic Greek word for “young woman.” The Septuagint translators, 200+ years before the birth of Christ, and with no inherent belief in a “virgin birth,” translated “almah” in Isaiah 7:14 as “virgin,” not “young woman.” This gives evidence that “virgin” is a possible, even likely, meaning of the term.