I'm swell - acceptable expression?

Hi, is this an acceptable expression:

I’m swell.

I know it means I’m OK/I’m fine but who uses it in what situation?

You usually hear the word “swell” to mean very well or very good in slang from the 1950s, but I think its origin goes back a few decades before that, at least. You hear it most on TV shows from the 1950s, or films from the '40s. It’s seldom used now, and when it is, it’s often used in an ironic sense, so when someone says, “I’m swell!” you have to figure out whether he’s really doing well, or if he’s doing badly and is just being sarcastic. There are a few people, though, who still use it in the old positive sense, without being sarcastic.