When we are young, we have a lot of "when I grow up" thoughts which we likely plan on fulfilling at the time we have them. Depending on our age, they may be of varying degrees of practicality. Most boys want to be garbage men when they are 2, and pro athletes when they are 8, but later on they may decide on other things like a house, or a certain car, or a more practical career aspiration, all to be achieved at a much later date. When we are young, it is totally acceptable to say this is going to come much later. This "I will do it later" context can stay with us in some form.
What is it you really want? Do you want a certain career that you do not have? Do you want a different level of fitness, or a dog, or a certain place to live? Instead of telling yourself you will get a dog when the time is exactly right, why not get one now? Instead of pursuing the career you want at a much later date, why not now? You are no longer a child who says "when I grow up" before many aspirations, so why continue to use that context?
If not now, when? Create what you want to create, the time can always be right if we decide it is right.