Most Facebook and Funnel Gurus will have you believe that you can test one funnel and become an overnight millionaire.
This is not true and that's the beauty of having a marketing strategy.
Marketing is all about testing and numbers. You can never be 100% certain that an ad or an offer or a funnel will work the first time. That's why it's important to split test each step of your customer journey, so that you can see what areas need improvement. Even when you have a strategy that is working, you can always keep testing in order to optimize it.
Keep in mind that things change in the digital marketing world (often) such as, algorithm updates, new competitor offers, or new advertising software. Through accurate reporting and consistent testing you will set yourself up for long term success and impact.
Don't be discouraged and don't give up if something doesn't work the first time. It's never a question of if marketing will work for you, but only when marketing will work for you. And that is up to how strong your strategy is.