You do not need a month and a developer to open. You need a short list of decisions made in order, and the discipline to skip the rest until you have a first sale.
Saturday morning: the shape of it
Pick a name, a logo, and three colors. Write one sentence that says what you sell and who it is for. Everything else on your site is downstream of that sentence, so it is worth ten quiet minutes.
Saturday afternoon: five products, done well
Resist the urge to load your whole catalog. Add five products with honest descriptions and one clear photo each. Five things done well beats fifty half-finished, and you can add the rest once orders are coming in.
Sunday: the boring parts that build trust
Shipping, returns, and a way to reach you. These are not glamorous, but they are the difference between a browser and a buyer. Write them plainly, publish, and send the link to one friend for a first order.
That is a store. You will change everything about it over the next year — but only because it is real, and open, and taking orders.