Probably not. It may take two to three weeks to carb up in the bottle.
If kegging, and using non-complex ingredients and not a lot of roast, it should be doable. Roasty beers sometimes take a bit longer to smooth out than beers without roast, but 20 days at room temperature could do it. The issue with bottling is just that it won't have time to carb up and smooth out.
It can be done. Ferment for 5-6 days, which should be enough time with a session stout and healthy yeast pitch. Bottle and condition for the rest of the time. You can speed up bottle conditioning by storing the filled bottles in a warm place. Might even considered swirling the bottles around to stir the yeast up to get it to work faster. You should have no problem having fully carbed beer in 24 days.
I think you can do it, but you might not love the beer. Pitch a ton of yeast from an active starter to reduce lag time. Ferment at the higher end if the strains temp range. Store bottles warmer if possible.