Sex when get positive OPK

This may be a dumb question but I like asking on here because it get responses from actual people. So when you get your positive opk and you have sex that day, even if you ovulate 24 hours later you can still get pregnant correct? Does the sperm actually live like 3 days inside? Thank you in advance! And I know it's probably a dumb question but I don't trust the internet 100%