By cutting, you have spurred the rhizome to grow, which normally happens in the spring. The danger is that the rhizome expends most of its energy sending up shoots that aren't exposed to sunlight long enough to return that energy to grow the root mass.
Read around here and you'll see people talking about little to no harvest the first year. That's because it takes the plant 3 to 4 years to establish enough root mass to support the full vigor.
On top of that, a "head start" is not always a good thing. You often want to cut back the shoots that first pop up for various reasons but in particular to get the growth cycle just right. If they start out too early, they will start budding out before the side arms are developed. That really hurts your harvest size.
But, what is done is done so let us know how it turns out.