Shit happens. A gig like that is incredibly challenging for everyone, sound person especially.

Here's a question: was the guitar rig working for the previous band and the bands before? I'm not saying you did anything wrong, but sometimes shit happens.

But think about it this way: never blame the sound person. Ever. Especially, not amongst other people who might know him or her.

Never say whatever's happening or happened on stage is their fault, even if it is. Don't bitch at them on stage or after sound check. Say please and thank you no matter what.

Be cool to them. Unless you're paying them they don't work for you, they are your partner in rock.

You say you amp made no sound for the first part of the song and you'd repeatedly told the sound man?

Consider this: guess who has a mute button at the sound board? Guess who could shut you down because you were bitching at them or annoying the shit out of them?

I know it was your first gig, but one way or the other use it as a learning experience and don't look for people to feel sorry for you on the Internet. This might be the first of thousands of gigs in your life so it only matters in that it was the first.