What have you always wanted to do? What did you say you would do once you had the [time/money/experience]?
What are you waiting for?
Perhaps your are delaying because of some prerequisite you’ve created for yourself (e.g., when I have enough money, when I have more time, after I’ve done XYZ). If this is the case, think about the real reasons of why you have delayed. Are you afraid that it’s not going to be all you thought it would be? Are you insecure in your abilities to take the leap of faith? Are you resistant to change? Or have your values and priorities changed?
If the latter is true for you, then that’s okay– what you’ve always wanted is not what you want anymore. And if what is stopping you is any other reason, then reconsider. Know it will never be the right time. You’ll never have enough.
This is it. You’re grown up now. Just do it.