Consider the following scenario:
Person A never ate a cake. Person B has eaten cake before. Now A has the opinion that A dislikes cake (and brings up several arguments), but B argues "You've never tried one, so how would you know?". So, is A's statement invalid now? And is this called solipsism?
Another scenario-questions as an example only:
How would you know that you are heterosexual if you've never had sex with the same sex before?
How would you know that your birthday present is bad/good if you've never opened it yet?
How would you know that cats are heavy if you've never hold one in your arms?