I need help? This girl is going crazy.?

I had sex with this younger girl yesterday. I am 18 years old and my friend text me telling me she is going crazy about what happened yesterday. I didn't use a condom but I made sure she wouldn't get pregnant. I didn't *** in her at all. She is freaking out thinking she is going to end up pregnant. Why is she going crazy? If she didn't want to have sex she should have said so. She seemed please with the sex anyways I don't get why she is worrying about the outcomes on sex sometimes then just enjoying it and calming down. How do I tell her nicely without being a jerk about it for her to chill and stop freaking out because I know I didn't do anything to get her pregnant. She clams there was precum on my dick when she went to suck it I didn't see anything but her fine *** on me. What should I say to her without being mean about it? She is a shy girl anyways so I have to be nice because she gets shy and she will stop talking and become depressed and everything. I think it's her young mind playing games on her I have yet to get a girl knocked up and I don't plan for the first one to be a 15 year old little girl that just needs to learn how to please men more and needs to chill a bit.