Dear Yvonne,
I only just discovered you now, I was on vacation.
Chalk paint is indeed sold for shabby finishes, but it is not a durable coating. You would soon have greasy corners on the desk that really represent shabby, the only exception is if you go over it again at the end with a sealer. However, this does not really make it more impact-resistant, only more wipe-resistant.
If it absolutely has to be this paint, then apply a thin layer of blocking material underneath, this may also be thinned down. This makes the top layer pull evenly. You can adjust the degree to which it pulls by thinning the blocking material. For that, I would be mean: I would, for example, use an impact-resistant water-soluble stair varnish, inexpensive and available everywhere. Then coat as desired. In case someone is less proficient in DIY than you: pulling means in this case that the liquid part of the paint is capillary absorbed into the substrate, the solid remains on top and forms the visible volume, which you see as structure and might not want.
In general, I would create a shabby look more with a colored primer as an undercoat and with (highly) pigmented, probably white waxes on top. It is possible to pep up such a wax with some pigment if it doesn’t cover enough, but dose the amount carefully or buy the suitable one right away. Waxes are easy to apply, great for retouching, and you can maintain them to some extent later if something gets too worn off. By no means do they attract dirt like chalk paint with its open-pored structure. But hard waxes also wear away little by little with frequent mechanical stress.
Latex paint is obviously possible at first, but I would advise against it. It does not stay nice for very long. Latex paint is actually a dispersion with an increased binder content. Binder is a pure acrylic in aqueous solution. Dispersion paints often contain fillers from the mineral range (heavy spar), which makes them thick and heavy. These fillers attract dirt. Latex paint is made wipe-resistant by the binder. This is expensive, which is why only the minimum amount is in it. The binder itself also does not dry hard: it forms a stretchable plastic film in its pure form when dried.
I hope you get a nice piece!
Many greetings, Gabriele