It's ok, no real context needed here. Anyway, this is slang of course. "To be (all) about something" simply means to like it. It can also be a way to agree with someone.
"What do you think about getting some McDonald's right now?" / "Yeah, I'm about it."
Somewhat recently, this has extended into the phrase "I'm about that [something] life" to essentially mean the same thing. Usually this more recent one gets used to encompass all factors about a given thing, with the added "life" essentially meaning you like everything about something. In some circumstances it is replaced by "lifestyle" which furthers this point. At the risk of sounding dumb trying to explain slang that changes almost daily, I'll give you an example.
I like living in California → I'm all about living in California → I'm about that Cali life
I don't think this is particularly common in the UK - although it might be known/used by younger people. It sounds like a bit of modern usage that may or may not "stick".
I needed to read Themahimahi's answer to know what it meant myself.