The main problem with this phrase is "I refuse myself". I think the best way to rephrase this is, "Starting today, I refuse to stay in my comfort zone." You could also start with, "From this day on" or "From today on, I refuse to stay in my comfort zone."

Your comfort zone means that you like to be somewhere where you can relax in familiar setting like in front of the TV in your lounge room or work in a field that you are an expert in. Example: I am a classroom teacher and this is my comfort zone. I would not like to be a principal.

Penso que esta é uma boa idéia e todos nós poderíamos aprender com ele. It's very nearly right. It is a normal sentence. It is something we usually say. In english a phrase is part of a sentence. From today, I refuse to stay in my comfort zone. Phrase, phrase. When talking about something that is ours we always say 'my' instead of 'the'. Por isso: my comfort zone. Not: the comfort zone. Sei que vocês costumam dizer 'o' em vez de "meu". Por exemplo: "a mão" ao falar sobre sua própria mão. Mas em Inglês, sempre dizemos "minha mão". Você não precisa da palavra 'myself'. Está implícito em Inglês pelo contexto.