Is it possible for my macbook pro to have a virus

I was browsing online, like usual, just like I have been for the last 5 years on my mac, and all of the sudden i get like 5 different pop up windows that tell me I have a virus, then my computer starts talking and saying "Virus alert" They told me to call this number, and i did. and the lady took my serial number and said that I would have to pay her a hundred dollars. I feel really stupid. I feel like its a scam, however I can't help but be paranoid.