Hey Victoria @Victoria,
So I encourage if anyone else knows other evidences or has some other thoughts but I will say the following.
If you look at the Jewish culture, it was veryyy crucial that every girl was a virgin. It was taken soo highly and it was a disgrace to the entire family and to God. Moses law also forbids any premartial sex and if someone forced a girl or in agreement had sex, they were forced to get married. Now in the story of Jesus, both Mary’s family and Joseph were devote and Joseph, when he found out that Mary was pregnant, he was going to call off the wedding. It was only because of the angel that he changed his mind when he told him that it was from God.
Also, to get a clarification on your question, are you asking if Mary was a virgin before she gave birth to Jesus or is the question implying that Jesus was a creation of sperm and egg. If it is the first one, her being virgin or not does not matter as long as we acknowledge that Jesus was placed in her womb without an actual intercourse via God (even if for some odd reason, Mary was not a virgin prior). If the question is the second one, it is implying that Jesus is not God, because created things are not gods but idols. As you know Jesus is the eternal God who was there before the world as the Son. So the answer would be if you believe that Jesus rose from the dead and is God, then you would come to the conclusion that it cant be.
Now these things were prophesied way before Christ that he would come via a virgin birth, like you said yourself there is the people around them who know the history. At the same time though, somethings just cant be proven and sometimes you have to look at the coherence of the story, have to connect other dots and look at the big picture to arrive to your conclusions.
John Lennox had this great quote he mentioned that was said by Alex Vilenken (well known physicist),
“An argument is what convinces reasonable men, and a proof is what it takes to convince even an unreasonable man”
I hope this helps.