What knife should I buy for my first EDC? I don't want a huge knife under 7inches total. I need something strong and durable
Considering your lack of experience with knives, I would highly suggest getting a spyderco knife. I have a spyderco resilience which has a rather large blade, but I use it for food prep. For EDC I suggest: endura, delica, tenacious or whichever you like the best. They are super easy to sharpen, a good steel to practice sharpening on (8cr13mov), and the ergonomics are incredible, fits the hand really nice. Opens up very smooth, and the spidey holes are great.
Or you can get an ontario rat 1, which has a SLIGHTLY better steel (aus8), has decent ergos-not as good as spyderco, but it's more people friendly-like you won't get weird looks for taking it out in public. It has thumb studs, finger choil and frn or g-10 handles.
Or you can look Into cold steel, I recommend the cold steel recon 1, or the cold steel american lawman. And all of these can be found on amazon