Your plants look pretty normal to me for ~18 days old. They should put on a lot more leaves, stem girth, and height in the next 2-3 weeks especially if you pot them up to 3-4" pots. You might have started them a little late though. Here in my area I start brassicas in mid June (Brussels) to early July (broccoli and cauliflower). Cabbage moths are a PITA when growing fall brassicas so be prepared with the BTK or insect barrier covers from the time you take them outside to harden off.

Not sure what the problem is. Small seedlings easily get root-bound in small containers. To the extent you've started them in very small trays, time to plant up or plant out. I always start my Brassicas in 9oz cups.

Thanks! ill have to move them hopefully theyll jump

Thanks lone jack i will cover and also havw BT