The lady at your lfs (local fish store) is absolutely correct! Ph is one of those things that are best left alone.
You are fortunate to have found someone at a shop who will be that honest with you. All too often they try to sell you a test kit for it which will only cost you money and give you something unnecessary to worry about.
Why not post an introduction in the Newbie section of the forum and let everyone know you are here? It's a very friendly place and I'm sure you will learn much and enjoy yourself while you're here.
Well, several said to me that pH was nessesary and I thought it was, until I visited a fish store with all there fish in pH 8.5 and they said that you should completely forget about it. I went that way and it saved me time and money and my fish are now happily swimming.