Geeks, welcome!
Not a rambling post, quite coherent in fact.
I don't have any experience with Android, but because the main language is Java, ehm, Dalvik ehm whatever, I think learning Java would definitely be a plus, if only to better understand documentation, interoperability etc.
But note that's really an off the cuff remark - was thinking about the situation with the Windows API where it helps if you know some C - which I don't...
... and which might be comparable to Android/Java now.
Well, I'll bow out now and leave the stage to the Android experts over here. However, regardless of which way you go, hope you'll try FPC/Lazarus anyway (perhaps on Windows, perhaps on Linux, perhaps on OSX) and have some fun with it
Hugs
,
BigChimp