Can i be pregnant if my boyfriend didn't finish in me?

Theoretically yes.: A man can leak semen even before the "finish.".

Yes: What most younger people don't realize is that some sperm can come out of the man before he actually ejaculates. That is why the "pullout" method of birth control is such a poor method. Talk to an obgyn about a better form of contraception. And if your period doesn't come, get a pregnancy test. Good luck.