Yep Tim, I say go ahead and enter Advanced- tell the judges before your flight which manuevers you will be leaving out and fly the Beginner pattern + any other maneuvers you feel good performing. You can have a list in your free hand so you don't forget anything- but write BIG- you only want to take a moment to confirm your next stunt, and get ready.
The stress level will be down, and you still get experience flying in competition for the judges. You get to see how well your current level of flying scores on a score card, and odds are if someone else has equipment issues ( or worse crashes) you will be above last place!
You can also gets some flights in on the practice circle, and there are always people willing to provide feedback / advice.