Best friend become boyfriend

Have you ever made a relationships with your best friend? I liked him when we were child but I didnt think that he like me. And now when we are adults he told me that he was and had feelings all theese years. I dont think that relationships between us are possible now but maybe its destiny? I dont know if I should try relationships with him cos if we will mess up with it we shouldnt be best friends anymore... do you think that we should try? (he dont know that I liked him).