I've spent a few days talking about how artists get themselves trapped holding impossibly large goals, goals that they can't even begin to pursue because they don't believe in their ability to complete them.
As I keep saying, if you don't believe you can do it, your mind is literally unable to enter the creative state that makes creative work possible. The belief that you can't becomes self-fulfilling truth, as you find yourself stuck, unable to move forward.
Now, these beliefs have very tenuous basis in physical reality. They come from our interpretations of past events and lessons, haphazardly applied to hypothetical future scenarios.
Sometimes the only thing holding you back is the misguided belief "I can't." Your goals aren't unrealistic or inflated; instead, your self-confidence is undersized.
Maybe you had parents who told you a thousand times, "You never do anything right." Maybe your junior-high-school music teacher told you, "You're not very good at music." Maybe your first performance experiences were painful humiliations.
And it's not just experiences from your past that knock down your self-confidence. There might be people in your life today who intentionally undermine your self-esteem. For example, bullies and psychic vampires who enjoy building themselves up by putting other people down. Or there might be family member or close friends who have begun to sense the positive vibes coming from your creative work; they might (correctly) fear that your success will change the dynamics of your tangled, dysfunctional relationships.
I can't go into detail about how to protect yourself against toxic people and clean up relationship messes — there are plenty of experts in that area who can guide you — but do whatever you have to do to keep their energy out of your creative space. Probably the single most important thing you can do in this regard is to keep the details of your creative work secret, except perhaps for a few trusted, supportive friends whom you select.
If you have family members who are threatened by your independence and success, don't give them a reason to push back. Instead, come up with a pathetic-sounding cover story. All that guitar playing that people can hear coming from your room? Don't tell them you're halfway through recording your debut album on Garage Band. Tell them you're just learning to play along with some Radiohead songs.
Anyway, if a legacy of people trying to discourage you has left you feeling thoroughly beaten down and discouraged, a feeling you've internalized as "I can't," then I have good news: There is a proven antidote. What you need is a massive infusion of encouragement, a steady diet of "I can." Find supportive people, and look up books of affirmations and other encouraging materials. It takes time to tip the balance against years of discouraging voices, but it absolutely can be done.
Meanwhile, don't try to push ahead with goals if you really can't muster the belief that you can do them. But start with smaller and simpler creative goals, and see if you're willing to suspend your disbelief in yourself and give them a try. It doesn't matter how small you start, because if you keep gradually moving to bigger challenges, you'll be doing big, impressive things before you know it. A pattern of success will help you feel bolder, and you'll build a habit of saying "I can."