Have I Reached my Limit?!

Here's my story: I was cubing in the Library using MobileCube Scrambler installed in my cellphone, when I encountered an amazing scramble and solved it in 26.xx, considering that I am an inconsistent sub30 cuber, it was a pretty good solve for me, but i was not satisfied, i want a sub20 solve! So out of my curiosity if i can reach a sub20 solve, i repeated the scramble and solved it again, and of course my time improved, i solved the scramble and got a time of 24.xx secs, but after solving ...