It could have been "just after", but "pico" is quite vague. It was definitely after 11 and it wasn't yet 12 and probably it wasn't even getting close to 12. It might well have been 11:30, but the speaker doesn't know exactly what time it was.We arrived just after eleven.
That seems like the best option if we want to include a range of about 11:01 to 11:30-ish. I'd say that "a bit" or "a little" would include no more than about 10-15 minutes after. Of course, these are all very subjective and gray.I might say "some time after eleven."