Splinter: "It's been a long time" to April

[Lou 500]

I spotted this quote before I was about to bash the author of this article for beating the dead horse about the aliens thing. But then I noticed that quote at the bottom and became intrigued:

And we see April’s first meeting with Splinter (Tony Shaloub), who greets her with the mysterious, "It’s been a long time."

At this point we can only speculate, but boy is speculating fun! What do you think it might imply? Either:

- As a child, April got a glimpse of her dad's test subjects (the non-mutated turtles and Splinter) and maybe Kirby even let her keep them as temporary pets before taking them to the lab, or she was introduced to them on a "Bring your Kid to Work Day"

- April's dad is actually Splinter, maybe not even entirely: When hit with the mutagen maybe he got fused with the lab rat or something they they became one being.

- Splinter is referring to the last time he saw and interacted with a human being.

Wanna post your theories?