As long as the fabric that you are knitting looks good to you and the gauge is right on now you will be fine. No extra knitting really.
needle size in the pattern is really a suggestion. That is the size that the creator got gauge with. Some knitters tend to knit really loosly while other knit very tightly. So you start with a gauge swatch using the suggested needles and the switch needle sizes as needed.
Good Luck!
