Getting Caught 😬😬

I’m a 16 yr old and still live under the roof of my moms house. Shes a single mother whose worked very hard to give her four kids the life they deserved. I invited a guy over and she walked in on us having sex. She freaked out and kicked the guy out. She thinks I’m gonna turn into a sex freak and go around having sex with anyone. I’m just upset bc she has a wrong image of me, and she won’t be able to see me the same. The guy and I work together as she’s threatening to take me out of work because of this. Help. What do I do?? I know regaining her trust is gonna take a while and I’ll probably just end up focusing on school and sports but I need to clear things up with her. Any advice??