Should I reduce humidity?

Your plant looks normal and healthy to me, without any issues and are a good size for 2 weeks old. Some plants are naturally slow growing at first, building roots before getting going. As long as your light is suitable, she will take off soon enough. Humidity will not slow growth and is not overly critical unless extremely high or extremely low. Worrying about VPD charts and having everything "exact", will not alter yields or potency by any more than one quarter of 1% of total quantifiable results. Growing should be simple, and not an exercise in "perfectness", as nothing in life is ever perfect. Besides, unless you get your flowers analysed by a laboratory, will you ever know if your buds have 23.457% THC or 23.673% THC???? Health, nutrition and the biggie, light quality, are the three major factors for obtaining prime flowers. 5% humidity either way is not going to do anything better or worse. Remember too, 18/6 light/dark is optimum for all cannabis, autos or photoperiod plants in veg. Personally, I do not see a need for any type of humidifier, so you save on your electricity bill! Cannabis actually prefers a dry climate and not rain forest conditions. Most Indicas come from the Middle East, places like Pakistan and Afghanistan, - not much humidity in those places. Even tropical Sativas prefer a dry climate, and are grown during the non rainy season, called, ironically, the "dry season"! Hope this helps,.......... Organoman.