why they so small, or are thye?

Pretty much what others said. Higher humidity with a plastic dome over them will speed up seedling growth. Also, temps should be in the 75-85f range. I would recommend you bring them inside at night as a bare minimum.

I like to use some kind of dome to keep the humidity up at that age.. a clear plastic cup or something similar

it looks fine and normal for a 10 day old. Cold temps DO slow the growth down a bit too and wouldn't personally take em outdoors at this age anyway.

I would say your probably rite about why there so small. Once the weather improves for ya you should see some better growth. Noticed your starting in large pots with your seedlings too so also make sure your not overwatering them at this point, and get a good wet/dry cycle going for them, making sure you let them dry enough before watering again. Cold temps and overwatering are a bad combination for seedlings. Hope this helps, cheers 💨