Should you accept the first offer?

Not automatically, and not automatically no. In my experience, the first offer is often the most serious one, and accepting it can avoid holding costs and the risk of waiting for a better one that never comes. The caution is accepting too quickly if the buyer's profile, the other agent's attitude, and the offer itself don't all hit the mark. If all three are above average, it's probably a good choice. I'll compare it against the market and your goals so you can accept, counter, or decline with a clear reason.