worried

So, last night I had a guy over and it was ok. I tried giving him a bj and I guess I am  out of practice and well he didn't orgasm. What he did do was pre-cum, which mostly got on my thighs and in my mouth. He later cleaned himself off with a towel and I wiped away some of my wetness with the same towel about a minute or two after him. Most if not all of the pre cum got into my mouth. Should I be worried that I may get pregnant?  Side note: I talked with some friends and him about it and they have all said that no it's not possible but you never know.