Pregnancy risks?

Hi, I'm a bit worried and... maybe I shouldn't, but I just need to be sure.

So... friday night, me and my bf had sex (not for so long though, we were both really tired) and he wanted to try something : penetrating me without a condom, but just going in to feel "my inside". I thought about it and agreed, he wasn't going to make any moves, he didn't cum before and wasn't going to cum inside me, so everything seemed fine (I wanted to try it too). He penetrated me, stayed for less than one minute, talking about how different it was from usual, and then went back "outside". I'm wondering, is there a chance of pregnancy? I know I was in a fertile window (thursday : 22% ; friday : 8%) according to this app... but, I just feel like I need to ask, even if my question might seem dumb. I'm 17 years old and I'm not ready to have a child yet so I try to be really carefull. Please, I need some help...