Tried sticking finggerrs down throat, but i can't make myself throw up. is it possible to not have a gag reflex?

Possible, not likely: It's hard to gag yourself so bad you throw up, just as it's hard to punch yourself so hard you hurt something. There are diseases where you could lose your gag reflex, such as stroke or brain tumor. The likely answer is my first one however, you just can't make yourself do it. And that's probably a good thing. If you're really concerned, go see an ENT for a thorough head and neck exam.