Betty, an AV node ablation does NOT offer a 100% chance of eliminating AF. It may in some cases, and it looks like it is highly likely in yours ( I don't know all your particulars, but your advising EP would). But I know at least one person for whom the AV node 'nuking' didn't work. What it does do is to reduce to essentially 'zero' the chances of getting RVR (rapid ventricular response, which is somewhat more dangerous than SVT and AF are) since the AV node passes on the SA node's original impulses down the Bundle of His and then on two the two bundle branches, left and right, and into the Purkinje Fibers (you may have heard of 'left bundle branch block', another heart rhythm defect). RVR encourages the left ventricle to begin to thicken in response to the extra work when it is cycling rapidly in consonance with a rapidly cycling atrium above it.
The way it works is this: the SA node sends out a 'beat signal', which travels outward, down to the AV node, but also through the septum and out into the inner endothelial lining of the left atrium, which causes the atrium to beat first (filling the left ventricle below it via the mitral valve). The same signal, moving away from the SA node, passes to the AV node which can actually re-signal the atrium to beat again, so that's one potential cause for AF. But normally the signal continues down the Bundle of His and ends up splitting and causing each ventricle to contact a fraction of a second after the atrium (the signal takes longer that way, so that beat comes later). If AF is formally diagnosed, and if the sustained rate is higher than 100 BPM, it is deemed to be 'AF with RVR', or atrial fibrillation with rapid ventricular response. This can lead to a tired heart muscle in time, and that is why instructions to ablation patients, or just plain AF patients waiting for treatment, to get to an ER if their rate is at 100 or higher for more than 24 hours.
I expect that you understand that an AV node ablation means a pacemaker as this is needed to do what the AV node does, and that is to pass on the beat instruction signal to both ventricles.