The gauge on the yarn label is probably without blocking, it's really just to put a yarn into a weight range - dk, worsted, bulky. I've learned the gauge given in a pattern is after washing and blocking.
You can take what you have now and block it out to see if it grows or not. It also depends on the fiber of the yarn - some will, most won't. Please don't stress yourself out, you're probably fine.
sue- knitting heretic