Question about pony tailed palm plants,?

A lady gave one that was the size of a small coconut and there were several long tough roots attached.I carefully re potted it in a eight inch pot with very rich gardens soil.I didn't expect any spectacular growth immediately but in three weeks this plant has grown fronds five inches long. Where I got it cats their had eaten the foliage completely off and I am wondering if this is normal for this plant to grow this fast. This plant is kept in a low humidity living room under partial sunlight. Is this normal for this kind of plant?