Just do it!! Otherwise...

Do you know how to tell a successful person from a unsuccessful one? The main difference is the way that they speak about their goals. And this applies to anything! This is about screenwriting but can be about wanting to lose weight (going to the gym or going on a diet), writing on a blog or any goals you may have. The difference between both people is that the unsuccessful ones say: "One day i will do this" "I hope to do this" and the winners set a time limit on their goals.
You wanna know something, that day will never come! The reason people say it is to not be responsible for their words, gives them a way out. There's never failure in "someday", that's the way out, but in return, you'll never be successful!
Now, if you place a time limit on the goal you want to achieve, it's the first step. Losers hate this because they hate failure, successful people are not afraid of failing because that's what they learn from. Every successful person will have allot of stories on how they tried and failed and how they learned from it.
So my advice is for you to just stop talking about how you want to "someday" do it, and start now. Go to one of my previous posts about how to start with your ideas and turning them into something. Just plan your goals, set a time limit/ deadline and get right to it.
Failure to plan, you're planning you're failure.