if it is done in less than 10 seconds from the time of the bite you live.
A tight thing around your arm will also give you some more time.
I would have my friends tie me up and wait to see if I turn or if I'm immune.
Let's just assume this moment you were bitten.
Now you have to deal with the zombie that bit you, stop panicking, and find something to cut your arm off in 10-20 seconds.
Edit: And then deal with the fact that your arm has just been cut off. Like disinfecting, cauterizing, and dealing with only having one arm.