content: It's possible, but there are two reasons I've heard that prevent most people from taking that seriously. For one, it's just vanishingly statistically unlikely. There are an incredible number of Earth-like planets out there, and those are just the ones that might harbor life in a form we're familiar with. For us to be first, we'd have to beat millions of worlds to it, perhaps more. (Our Earth is also much younger than many similar worlds, so we have no reason to think we got a head start on life in general, either.) Second, even if we are the first... that's just not particularly useful. We're not likely to be able to detect less advanced life in deep space, at least not for a long while yet. Granted, it's an open question whether we could detect something more advanced either, but theoretical constructs like Dyson swarms or radio emissions are possible indicators we could potentially see.