I've had the same scare before.
We didn't have sex, I just tried putting him in me.
Then I was worried for a month.
I wouldn't get too worried.
It is extremely unlikely to happen.
This isn't good to admit but half the time I don't use condoms during the first couple minutes of sex (when its just pre cum) and amazingly I haven't gotten pregnant. I know its not good, don't need a lecture.