I don’t know many unmarried orthodox Jewish men in their 30s today. The notion of one remaining unmarried into their 30s 2000 years ago seems implausible too.
And for the record; the Bible doesn’t say that Mary was a virgin either. If she and Joeseph hadn’t been getting jiggy, he is unlikely to have been willing to marry her when she revealed that she was pregnant. He’d have disowned her immediately if he thought she had had sex with someone else. The ‘Immaculate Conception’ refers to when Mary was concieved free of Original Sin, not when Jesus was concieved.