I start off by saying Im a beginner and this is my first course! lol, but I found this was a little confusing at first and thought to mention it incase someone else hit this problem.
I had serialized my fields and my beginning values were minX as 0 and maxX as 16 - I was trying to work ahead 
so when I corrected it to be 1 and 15 in the script it was still not working, as running the game the paddle was still being limited to the original values.
Only when I looked into the inspector for the paddle did I realize the values there were the 0 and 16.
Once those were fixed the game behaved as it should.