I wouldn't get knocked out if i were you , unless the dentist seems to think its essential..
I had mine out a few months back , after ignoring repeated messages from my dentist.
I'm man so i wont say i was scared , just aprehensive..
But all in all it was easy and painless , the needles they give you now work great.
One hour , everything was out , 1 stitch on the left side nothing on the other.. tender gums for a week then your a-ok
Don't stress over it. I did and it wasn't shit..
If you get knocked out, no big deal either. More people choke and die on spoons every year than die from getting the gas..
I think the way they do it now is, they give you an i.v. and a little gas to get you under, then they insert a tube down your throat while your passed out and pump small amounts of gas down into your lungs as your vitals rise.
I had my adnoids removed and thats what they did. I was freaked about that too. And again it was no big deal, just a little unnerving..