Ashamed of a handjob?

So a while ago I was at a party and gave a guy a handjob through his pants. Now this girl form my year wants to expose me in front of the whole school because she hates me. Is this something to be ashamed of? I’m 16. Was it wrong what i did? What should I do? Let her tell people? Stand up for myself? Apologise? Accept what I did? HEELLLPPP