Replying to I almost became a pedophile today

so today I was hangin out in Paris and this really hot girl from Italy comes up to me and starts hitting on me. so we talk a bit and eventually we make out. this girl is in Paris alone shes 5'10-6'00 feet and she looks in her 20s so we go back to my place and continue making out. she starts undressing me I start undressing her and she says "I hope you dont mind im only 15" at this time I didnt know what to do. I told her I wasnt comfortable having sex with a 15 year old even if she wasnt a virgin and I showed her ski movie trailers and Family guy until she was ready to go at which point I accompanied her to the subway station for her to go back home.

now im not sure if I should have gone all the way or if I did the right thing. im 19 and in the US I feel uncomfortable with anyone under the age of 18