I boiled my first ever brew over real bad. Watched it like a hawk for almost 45 mins, was getting concerned my electric stove didn't have the oompf to boil it. So I went to take a quick piss. Bad idea, massive boil over.
But! It worked it fine anyways. It was a porter, and it was delicious, and I drank 5 gallons of it in 2 weeks, best beer I ever drank.
So don't worry to much.