I'd personally watch it right away if I don't want spoilers getting into my face. I watched it, and loved it. Go watch it and enjoy yourselves. That's the fun of riding along with the movie. You have NO idea whats going to happen in this movie. Like who dies or lives. Unless you spoiled yourself, which takes the fun out of the movie.
But if you watched the movie, something tells me some of the characters might have to sacrifice themselves in the next one. So some of em might be permanently gone after Avengers 4. I might be wrong, but who knows. You'll know when you watch it.