I'll echo what KP said. Both of my peach strains, Jays scorpion and the bhuts are always a struggle to have normal looking plants. I see other people on here who have plants that look like "normal" plants. Mine are usually paler or yellower, dropping lower leaves and just in general looking odd. Mind you they get the same soil, light and water as all my other "normal" looking plants. I barely fertilize so excess nutes ate not an issue with mine. Maybe not enough but not too much. I have found they really seem to grow the roots and don't tolerate being root bound. I usually plant up once my plants have a set or two of real leaves. Most of my plants are developing good roots at that point and not close to being congested down at the bottom of the cell. Now I start checking the peach plants earlier because even though they may not be big up top their roots are going crazy. Maybe they are real sensitive to their roots. But once in the ground they seem to get happy and grow fine. Long windedly that being said I've not had any with leaves looking like yours. With the focus issue it's hard for me to see the blotchy brown/light areas on the bigger leaves. But the twisty crinkley leaves I would think possibly it's a genetics thing. You said she has always been smaller (kinda like a runt). I do have some plants (of any variety) that have similar screwy looking leaves when they are first getting their adult leaves but they seem to grow out of it too. These are quite often the slower germinating, slower growing plants out of a batch of seeds. I use Ocean Forrest too with good results so you should be fine there.
