Doing a search of the AMA club locator shows that there are 5 AMA sanctioned clubs within 6 miles of Dublin, so it's probably a good likely hood that you may be within radio range of one of these clubs. As a good safety buffer you want to make sure that you are at least 3 miles (as the crow flies) away from any existing flying field. If you are within range of an existing field you could lose your plane from their radio signals, or worse yet you can shoot one of them down. Trust me, if you bring down somebody's $4,000 airplane they're not gonna be happy.
What's best is you don't even need AMA registration in this county and city to fly in Gov't owned property. Dont' get me wrong, you can still get into trouble if you cause damage to property or people.
This is one aspect of the AMA that many people overlook, insurance. The AMA membership also comes with a liability insurance policy that will cover damages in the event that you damage property or injure somebody. Not too long ago I was speaking with the gentleman that handles the insurance claims for the AMA and he told me that they recently had a claim submitted that was close to 2 million dollars!!! I for one know that I don't run around with a spare couple of million dollars in my back pocket. Because of this I readily pay my AMA dues every year in order to have this insurance. As Jetmech05 said, in this country everybody is pretty much lawsuit happy and you can count on being sued if you hit somebody. And since you're only 14 that lawsuit is probably more than likely going to be against your parents, I'm sure they will really enjoy that. The insurance you have with the AMA will protect you and them from the financial damages involved with a lawsuit.
I'm not telling you these things to try and rain on your parade, but rather I'm just giving you these thing to think about before you fly in a public park. Over the years I've seen many new pilots that just aren't aware of these things when they are getting started. That's what I'm doing here, just giving you the information about these things.
Ken