This is very important as I have just experienced it.
When browsing pages on you android phone, you may come across a message telling you that you have 13 viruses on your phone, for whatever reasons ( mine said that I had been clicking on porn websites) but I did not. They will then set a timer and ask you to download an antivirus app from the play store. DO NOT DOWNLOAD IT. I went to check on google and it said that this is a SCAM to incorporate malware into your phone.
What you should do:
Use a trusted antivirus software like AVG to scan for any viruses on your phone, and tell your parents. I do not want anyone to fall victim to this.