There's that quote "What would you do if you knew you could not fail?" But that makes no sense to me. No one who tries anything is fail-proof. I'd rather ask, "What would you do if you knew you'd fail repeatedly but that failure would lead to success you can't even imagine now?"
Would you try? Of course you would. Because the results are worth it, even if the shame and guilt of failure stings in the moment. This is life. And this is parenting.
You are going to fail. You'll fail yourself whenever you aren't the parent you want to be or think you should be. You'll fail in your non-parent life and duties because sometimes life is too overwhelming and you have too much on your plate. And you'll fail your kids sometimes, too.
That's the one that stings the most. When you fail your kids. The first time your child is in your arms you look at that sweet face and vow never to do anything that will hurt them. But part of being human is being flawed. Making mistakes. Sometimes making mistakes that really hurt someone. But hurting your child doesn't mean everything's broken. It means you learn to repair things. It means you take the rubbed spots and that's where you grow closer. Stronger at the scars.
The only way to avoid failing as a parent is not to be a parent. And you're a parent, so you'll fail sometimes. Be gentle with yourself, then rub some dirt on it and hug your kid and get back in there. You're worth it, and so are your kids.