They look like the lights to far away. Very stretchy.
The lights are six inches above the tops.
What kind of light are you using?
T5 HO eight tube, 40,000 lumens
It does look stretched. That stem looks strange. Possible over watered and damping off? Hard to tell from the pics.
Iâd answer few questions.
Lights
Light cycle
Seed type and strain
Water schedule etcâŚ
Trying nutrients yet
Soil
Temp/humidity
And then ring in some mentors. @MattyBear @dbrn32 @BigDaddyCain @elheffe702
This is day 18. stem is not strong enough to hold the top up. one seems to be wilting.
Less water . Will the stem catch up with the tops?
How often and how much are you watering? The seedlings donât take much water. Definitely not water to run off or water directly next to stem. Pour water around it in an invisible circle about 1" away. Let it dry out pretty good before watering again.
One of the more seasoned pros will pop in shortly Iâm sure
Have been lightly misting twice a day.
What soil are you using? Some soils like Coco retain moisture longer and take a lot less water.
@PurpNGold74 could you take a look.
If its just stretching, Iâd bury the stem with more soil. If its damping off, doing that might make matters worse. I try to have a little fan blowing to help the stem gain strength. At this point, her stem is too weak. A fan would blow her down.
Thanks for the tag J!
Welcome to ILGM @joep
So far all sound advice. She looks stretchy (low light intensity) not familiar with that bulb. But if you put ur hand under it (just above the plant) and its not warm, you could probably run it a bit closer. As the girls get older id definitely look into getting a stronger light. Just fyiâŚ
And as @TXCanna (great advice on the watering in a circle away from the stem) n J pointed out, she is definitely dampening off. Overwatering a bit⌠ur soil looks appropriately wet. The problem is⌠the peat pellet!
These things leech and hold onto waaaay too much water. U see in the photo its extremely dark.
To fix, firstly bury that stem. Try to get at least halfway up to the bottom leaves. Further if possible. Then lightly mist the mound. Please avoid the stem. And from now, until sheâs a more firmly established young lady, water around the âexpected rootsâ. You want them to âchaseâ the water and force root growth.
Welcome to ILGM @joep! @PurpNGold74 has you covered. Thatâs exactly the advice I wouldâve given. Iâd only add that some airflow to get the leaves to just flutter a little will give the stem a workout and strengthen the stem, once youâve buried it some. Sheâll be okay!
What size pot are you in at this time you are definitely over watering small plant in big pot will make it super easy to over water best time is to Let her dry out and if you are useing T5 lights you can put them like 5-8 inches away and donât add nuits for atleast 3 weeks that is about the time veg will start and until then when you do water you want to water 6âin away from plant 
you want her roots to go and search for the water it will cause the plant to strengthen up that stem so it can hold the plant and welcome to ilgm only dumb question is the one you donât ask we are here to help beat we can
No problem at all my guy. Just confirmation. U know im always up for a second opinion. 