Henry Ford famously said that whether you believe you can or whether you believe you can't you're always right so you had better believe you can if you want to succeed in life.
I may believe, for example that I am good at painting and drawing but not very good at sport, that I'm good at cooking but not very musical ... and so on.
Many people at the time thought it was impossible for a athlete to run a mile in under four minutes but not Bannister ... what was the difference between Bannister and those doubters?
Statements that are negative are often dogmatic, rigid and inflexible - they hold us back, offer no way forward, and as such, are of little help to us.
Significant experiences during the formative years of our lives can have a huge influence on the formation of our beliefs -both limiting and empowering.
These statements aren't 'true' - they're just stories we tell ourselves. These stories however, like any good story can be remarkably convincing and believable.
... but this is simply not the case. Limiting beliefs can be changed (it may take some effort but they can be changed). In fact, you have already changed a number of beliefs