Im getting in trouble

So today is the last day of school, so i decided to go out today with a guy friend and i didnt ask for permission bc i didnt think i was going to take long. I got out of school at 3:30 We went to go get icecream and then at around 4:50 my mother calls me (shes at work and so is my dad but my sis is at home) and asks where im at and with who, i got scared and i didnt know what to say so i just said with my friends eating and she got very mad and now when she comes from work shes going to talk to me. Ive never gotten in any trouble so im really scared. Im pretty sure my sis told on me( we dont get along) but now im really getting in trouble shes gonna probably ask me so many questions. I know i should have told her but i never do anything bc she doesnt let me i guess she doesnt trust me and all. To be honest i dont like going out i really dont and so i never do and im also a good student, im really focused on school. Ive never done anything bad and i dont plan to. Im just scared kinda right now , shes getting home at around 11:20pm. I dont know what to tell her, i dont want to tell her i went out with a guy bc ive never have and she might freak out, so idk what im going to say! I need advice/ help.

Update: thank you for the good advice !!! Also im 17 and never dated and rn i dont plan to date, maybe until college 🤷🏻‍♀️ I’ll see. And it went fine, mom didnt get me in trouble but now she just wants to know everything, she wants me to tell her everything that happens. She told me she wants me to tell her where im going with who etc from now on. Also she wants me to have trust in her. She knows what im going through and my mother knows how to treat these situations bc she had to take care of her five sisters when she was younger, since she’s the oldest! I love my mom a lot thank you girls again for the advice!!