Realizing that you suck at something can be humbling for some. Others get upset and angry when they are terrible at executing something that requires skill (hint: this is most things, so we all suck very badly at a LOT of different things). Others might simply not care.
No matter how you feel about it, understanding where you are and what stage of learning you need to get to in order to successfully build that particular skill is essential.
When we are terrible at something, and we know it, this is called the conscious incompetent stage of learning. In other words, we are aware of how bad we are.
Once we know how bad we are at something, and we wish to improve upon that skill, then the goal is to move into the conscious competence stage where we are executing repetitions of a particular skill over time in order to become better at it. If we stay in this stage, then we have to use mental energy each time that we engage in the said task.
With something that we do that isn't frequent enough to have an impact on us either way, then it probably isn't a big deal when it does take our mental energy.
But let's say it is something that we work on daily like improving our nutrition habits, then this can occupy a lot of mental real estate and become draining if we are getting our repetitions in the wrong manner.
This can lead to burnout and falling back into old habits.
The goal is to fall into the stage of learning identified as unconsciously competent. In other words, you spend zero mental energy on a particular tasks because it is now second nature.
This is why when trying to create better habits it is best to start small & simple. The smaller the tasks, and the easier it is, the easier it will be to transition that behavior to "unconsciously competent". You can then start build on top of that small, easy tasks with more larger, more complex tasks as you go through time.
Progress won't be linear so what you do by starting off with the small, easy stuff is ensure that if you fail months down the road when you try that new complex behavior modification that you will still have the small, easy stuff to fall back on that you don't even have to think about now. You're in a healthier place because if you would have taken the complex approach right off the get-go and failed, then you would have had nothing to fall back on.