I used to be like this but finally figured things out a bit. As a teen that kind of attention was just too much for me and I would barely speak. In my early 20s I could reciprocate but still not identify flirting correctly in all cases. As with many AS traits I think this is normal for many people, it's simply more extreme and longer lasting in our cases.
My problem was figuring out the differences between friendly and flirting. Ive made more than a few unwelcome passes in my life. But then, that's not unusual for men either. All of it got better with age and experience but there is still a blindness at work on some level.