As much as we complain and panic, the S has not HTF yet. It is the same old world that we have been living in but with higher costs. I recognize that this is going to change, but God only knows when.
With that in mind, I think that it is extremely important to have a small vegetable garden right now, not too big, not too small. Don't worry excessively about the size, or yield or canning the stuff. Just learn how to work the soil and what plants like your plot. Get an idea of the rhythm of the year. Figure out with this garden what pests you have, what weeds you are going to have trouble with, heck, what tools you need to make the garden work without breaking your back.
This is your "going to college" garden. Because, lets face facts, your garden isn't going to save your life this year if chaos descends and the world goes to hell tomorrow. This is your chance to learn how to garden the year after the SHTF.
There are skills that you can acquire, gardening is one of them. The fresh veggies will do you good and the mental cleansing of pottering about in a garden is good for these high stress times. But more important as a prepper, you have to start developing skills that will make your life better in a rougher and less resource rich America. In a chaotic environment, yield in a garden can be phenomenal (I would wager you could easily get a couple of hundred pounds of potatoes out of a back yard).
In my opinion, the skills that you can take time to develop now are going to serve you as well if not better than the stores of food or number of guns or ounces of gold. All of these things will all be useful, but skills are not as easy to count in your basement, so please, please make sure that you don't neglect your skills.