Is It Possible to Get Pregnant While Naked Grinding?

So last night, my partner and I did some naked grinding in his car. I'm 17 and still a virgin, but I have a feeling that some penetration may have been involved. There were a few times while we were grinding that I could've sworn that I felt it inside me. The first few minutes we grinded unprotected until he suggested that he put on a condom so that no pre-cum/sperm would get in contact with my vagina. He never ejaculated (even w/ the condom), but I'm not sure if there was any pre-cum involved before the condom was present. My question is if there was any pre-cum involved, is there a chance that I could get pregnant? I've heard from many sources that pre-cum may be potent enough to cause a pregnancy, including a friend who had a pregnancy scare due to having being pre-ejaculated inside her. I asked my partner if there was any pre-cum involved while he grinded, and he assured me that there wasn't, but sometimes you can never be too sure. Also should I take plan B just in case? I really don't wanna worry about a possible pregnancy at the moment.