You are wrong. Not just slightly, but badly enough that I
could not in good conscience ever recommend you for any
programming job until I was convinced that you had learned
from your mistakes.
I leave it as an exercise for you to read Applied
Cryptography and figure out how to crack your own
scrambling algorithm. A hint. If you xor 20 times it is
the same as having done one xor. (Albeit against a
different key than any of your original 20.) So it does
not matter how well you have managed to confuse yourself
about what you have done, to an attacker this is an xor,
and if they get 2 messages written in English encrypted
this way, they are going to have little trouble reading
both of them.
Just because you don't see how they can do it, doesn't mean
that they can't. Or even that they will find it
particularly hard.