Can you get an STD from someone who has never had sex or has never been sexually active?
It is very unlikely, but possible. Some people, for example, are born with HIV, which they can pass to other people later in life when they start having sex. People can also pick up herpes through casual kissing — even from friends and family. Their herpes infections can then be passed on sexually.
The chances of this happening are rare, so it’s not something to spend time worrying about. On the other hand, it’s another one of the many good reasons to always use condoms when you have sexual intercourse.