Then dont wait, lol. Just makes sense to me to have them develop a bit before putting them right outside, but im sure they woudl do find just planting them whenever if the temp is good
wait longer man. I didn't realize those were dixie cups though.
I dunno for sure, as im no expert but I assume that may be too small to get a nice root system going. You may want to transplant them to a regular cup, but that could prove to be pointless. I just have the picture of how small a dixie cup is and I thought those were like 2oz. Which I can't imagine a root system being able to be very strong in.
If you check out that link, it gives you an idea of how big the plants were when shamegame transplanted them to outdoors.
and make sure your light is close enough to ur plants, looks like it may be kind of far away.
other than that, keep doing what your doing. let them grow, depending on your lights somewhere around 9-15 days from sprout, till I would put them outdoors. Stay positive and stay patient, it will work out