Yellowing right off the bat... with a shitty pic.

Alright, first off I apologize for the picture quality. I have a phone and that's it, for a camera. Second, I'm using a soil-less mix with pearlite and peat moss. And I'm 100% sure there's no burn. When I tested my soil it went from 5.5 when I started testing, to 7.0 when I let it sit for a while. I think that might be the problem. If there IS a problem.

Alright, there are the two normal little leaves of a sprout, and then there are two TINY little true leaves. One of the two little round leaves is yellow at the tip, and the stem is a shade of purple. Picture below, but it's next to useless.

Peat moss is evil to try to grow with by itself, and perlite is nonreactive so it doesn't count.
Your soil pH is too low because peat moss sucks.
That's why your seedling is probably going to croak.
Use regular potting soil that has a higher pH.