Welcome to the board and welcome to the wonderful world of BP ownership!

I don't think there are any worries of your BP killing anybody! And, there are no reports of them getting to 20 foot in length.

I don't mean this the wrong way but did you do enough research before getting your BP? Reading up on them some more will settle all your concerns mentioned. This site alone will give you lots and lots of information. Check out the stickies on this site at the very least.