Sweetie, listen, the first thing I'm going to say to you is this:
Don't blame yourself for being scared. I mean it. The way you're feeling, the things you're considering, are huge life changes. They are. And your mind is trying to keep you in your comfort zone by injecting fear when you think about stepping out of it. It happens to the best of us. It's part of an ancient defence mechanism designed to stop us getting eaten by sabretooth cats the size of a small car. And it's very powerful.
It isn't a question of blame. It's simply that fear of the unknown making it hard for you. It happens. Even with a will of iron.
The thing to do is to try and not focus on the mountain you think you have to climb, and all the variables that come with that. I know sometimes we think that the process is a chain reaction of things you have to factor in all at once. And god, that can be a scary prospect. You feel like once you take one foot forward you're on a downhill slope that just makes you feel like you're speeding up out of control.
It doesn't have to be like that, though. If you focus on one thing at a time, it makes stuff far easier to deal with. There's no "ohmygodIhavetodothisandthisandthisand... *hyperventilates*"
Consider the first step in your plan. The one to see a therapist. How about just focusing on that one? Forget the rest, for the moment, and just think about taking that one step. It doesn't obligate you to do anything further, just have a chat with someone about how you're feeling, what kinds of options are open to you, just find out more about what kinds of things you want for yourself, you know? IF you want to take things further after that, then cross that bridge when you come to it. But in the immediate future, maybe just focus your attention on getting that first appointment set up, finding someone you like the look of, thinking about stuff you want to talk about and questions you may have. Does that sound possible?
Once again, don't be so hard on yourself for feeling scared of what might happen, sweetie. That's millions of years of evolution trying to keep you safe. It can be a good thing, in some cases. But it doesn't have to control you. Take it one step at a time, manageable things you think might possibly be within your scope to handle. Makes the whole thing a little less daunting.

*extra big hug*