Just watch the plant, number them and take notes. You will want to clone the desirable plants so you can slowly hunt your favorite plant out of the bunch. Looks like it's a little runt but hard to judge when they are so young and from seed.
Never get rid of a plant until you've smoked it, I've judged plants too soon and threw the cuttings out and regretted it when the plants blew up late bloom or ended up being good yielders.
The last seedlings I grew of MAC Muffin from Tastebudz I didn't like how this runty seed was growing and almost threw the clones out again but here's how it turned out and I'm still growing it. Smells like berry candy and is completely purple with no temperature shenanigans or special treatment.