What is considered Rape

I'm 16 and I just got back from a trip with 24 other teenage exchange students. During the holiday, I started seeing on of the other students. One night we went for a walk, I stopped and sat down to look at the stars. He puts his hand under my shirt and was touching my chest (which I was okay with) he asked if I wanted to go any further, I said no. We went back to cuddling and kissing and a few minutes later, I felt his hand slide into my underwear. I grabbed his hand and said no. He said 'come on its okay' and kept pushing and I kept resisting but eventually, his fingers were inside of me. I pulled his hand away another few times but he kept just telling me it was okay. I just have up and lay there until he was done and he picked me up off the ground and walked me back to the rest of the group.