Is this normal stem size?

Your plants look fine man. Your at such an early stage calling a stall or whatever you think you might have as to why they not growing, well, it's too soon. Just sit back let them get some true leafs going and start on a light diet of around 3-500ppm .7-1EC ambient ppm/EC of water included. As for your light. It'll okay but after about a week or so start bringing it up. Idk what light you have but 60-70% for veg 45cm away and for flower 100% and depending on your co2 or light guidelines set at 20cm or 30cm your light will tell you. Good luck. Good luck bro.

I agree increase it to at least 40 even 60. Once they pop out they can handle higher light intensity very quickly.

Plant looks just fine, 40% at least would be better than 25%.

its good that they stretch a bit. a little space between the medium and the vegetation will provide better air circulation at the bottom of the plants. also leaves are supposed to be flat. thats not a bad thing. if they are drooping you got a problem.