How do we know where that step is?
Typically when talking about stepping off the deep end, it's a place of no return. I'd like to think that once you're in the deep end, and you grow accustom to it, it's not so deep anymore. Deep is a word that means something different to all of us and depending on your situations and experiences, could mean something much more than it does to the rest of us.
Any time that I've "gone off the deep end", I've found myself growing faster and stronger than anytime before. It really is sink or swim in this case. When we come across an apparent line of the "deep end", it's easy for us to turn away and walk back to where we can easily keep our heads above the water. Walking off into the deep end is scary yes, but not as bad as our fears would like us to believe it is. Make that plunge, immerse yourself in to the "deep end" and see what happens, it might actually surprise you.