advice please

So me & my boyfriend have talked so much about having a baby, getting married, moving in all that just that we wanna end up with each other. Yesterday we got caught up in the moment & he came all the way inside me. I live in a mexican house hold so im scared to come out pregnant living at home because of my dad, otherwise i wouldn't mind. My question here is if i should take plan b or just let it happen? My fertile window ended a little over a week now, im supposed to start my period by Thursday or Friday. Like what would u do if u were in this situation?