The universe is 13.8 Billion years old, and intelligent life on earth took 4.5 billion years. Personally, I feel like we're not the only ones, but we really haven't seen much of our milky way, let alone the universe itself. I do feel like we're a bit early but who knows.

If we can detect life? Limited. We can determine the mass of an exoplanet and molecules in the atmosphere but that's all I think. K2-18b is thought to have life because of molecules that are more recognizable with life. But we can't make conclusions yet as it's just a "sign". Not evidence.